Geometry using 'A Tangled Web'

Updated by Michelle


Ages 10-16

  • Basic angle rules
  • Angles and parallel lines
  • Angles in triangles, quadrilaterals, polygons and circles


Use your angles skills to solve cunning angle puzzles to reveal a path through each level's maze of tangled webs and reach the goal.

Click 'Play' to get started, then 'OK' to skip past the family portrait.

In this game, you control a tiny robotic spider named Itzi, who needs to rescue his family members, and return home! As you rescue family members, their images appear in the portrait – save everyone to complete the painting!

  • Click on the coloured angle (?) then use your keyboard or on-screen keypad to type in the correct answer.
  • Collect all blue Glo-Flies - Rotate the cog by pressing the left and right arrow keys to roll Itzi around, and collect all the blue Glo-Flies to activate the Warp Gate to exit (when in Window mode, you can also use the A and D keys). If you prefer, you can also rotate the cog by clicking on the arrow buttons to the right of the screen.
  • Special gold Glo-Flies are optional - these appear on some levels. They're usually tucked away in hard-to-reach places, designed to challenge expert players. If you can’t reach one on your first play-through, that’s okay – just move on and come back later when you’ve honed your skills!
  • Coloured lines blocking path to Warp Gate - to remove the line by answering the angle correctly. This allows Itzi to pass through to the gate. If the answer is incorrect - the line remains in place and Itzi loses energy.
  • Removed lines re-appear after a few seconds, but can be removed again by clicking on the angle (you won't need to solve the puzzle again).
  • Itzi's energy - if it runs out, you fail the level. Check the bar on the top-left of the screen. Itzi loses energy if he hits the cog rim or bumps into dangerous obstacles, such as Laser Walls and Spike Balls.
  • Use the Restart Button on the bottom-left corner of the screen (next to the 'Pause' and 'Help' buttons) if you get stuck and want to start the level afresh.


There are 6 stages to this game. Complete the relevant stage and beat the Target Score to earn a medal (Bronze, Silver, Gold).

  • Stage 1: Basic angle rules
    • Angles at a right angle
    • Angles on a line
    • Angles at a point
    • Vertically opposite angles
    • Target Score >>> 40,000 (B), 70,000 (S), 92,000 (G)
  • Stage 2: Angles and parallel lines
    • Corresponding angles
    • Alternate angles
    • Co-interior (Allied) angles
    • Target Score >>> 32,000 (B), 66,000 (S), 96,000 (G)
  • Stage 3: Angles in triangles
    • Angles in a scalene triangle
    • Angles in an isosceles triangle
    • Angles in an equilateral triangle
    • Exterior angles of a triangle
    • Target Score >>> 32,000 (B), 66,000 (S), 96,000 (G)
  • Stage 4: Angles in quadrilaterals
    • Angles in a rectangle and square
    • Angles in a quadrilateral ie. a quadrilateral with no special properties
    • Angles in a parallelogram and rhombus
    • Angles in a kite
    • Angles in a trapezium
    • Target Score >>> 36,000 (B), 70,000 (S), 104,000 (G)
  • Stage 5: Angles in polygons
    • Exterior angles of a polygon
    • Interior angles of a polygon
    • Target Score >>> 40,000 (B), 74,000 (S), 112,000 (G)
  • Stage 6: Angles in circles
    • Triangles in circles
    • Radius and chord bisection rule
    • Right angle in a semi-circle rule
    • Cyclic quadrilateral rule
    • Angle at the centre is twice the angle at the circumference rule
    • Angles in the same segment are equal rule
    • Radius and tangent perpendicularity rule
    • Alternate segment theorem rule
    • Target Score >>> 40,000 (B), 74,000 (S), 110,000 (G)

Each Stage consists of 20 standard levels. When you first play a Stage, only Level 1 is available; as you complete each level, the next in sequence unlocks automatically.

In each Stage, as well as the standard levels there are four secret bonus levels, each containing a special challenge designed for gaming masters! To unlock the first bonus level you must achieve C Rank or better in all 20 standard levels; to unlock the second you must achieve B Rank or better; to unlock the third, achieve A Rank or better; and to unlock the fourth, achieve S Rank.


Your score for each level is the sum of four values:

Level Score = Energy Score + Blue Glo-Flies Score + Gold Glo-Flies Score + Time Bonus

Example 1: You complete a level with 75% energy remaining (3,000 × 0.75 = 2,250 points) and with 78 seconds left on the timer (78 points). You collected 3 blue Glo-Flies (3 × 500 = 1,500 points) and no gold Glo-Flies (0 points). So your score for the level is: 2,250 + 1,500 + 0 + 78 = 3,828 points.

Example 2: You complete a level with 40% energy remaining (3,000 × 0.4 = 1,200 points) and with 143 seconds left on the timer (143 points). You collected 2 blue Glo-Flies (2 × 500 = 1,000 points) and 2 gold Glo-Flies (2 × 1,000 = 2,000 points). So your score for the level is: 1,200 + 1,000 + 2,000 + 142 = 4,343 points.

Your best score for each level is recorded automatically. The scores for all levels completed in a Stage are added together to create the Stage Score, and the scores for all unlocked Stages are added together to create the Total Score.

On completing a level you are awarded a Rank of either C (OK), B (Good), A (Great) or S (Amazing!). These are defined as:

  • C Rank  Complete the level with score equivalent to less than 66% energy remaining and no time bonus.
  • B Rank  Complete the level with score equivalent to more than 66% energy remaining and no time bonus.
  • A Rank Complete the level with score equivalent to 100% energy remaining, all gold Glo-Flies collected and no time bonus.
  • S Rank  Complete the level with score equivalent to 100% energy remaining, all gold Glo-Flies collected and a fast time bonus. S Ranks can be tough to get – look for shortcuts and tricks that will help you save seconds!


  • If you can’t work out how to find an angle, use the in-game maths help
  • Angles making a straight line add up to 180°
  • Angles meeting at a point add up to 360°
  • The angles in a triangle add up to 180°
  • In an isosceles triangle, two of the angles are equal. If you know one of the two equal angles, double it and then take the number you get away from 180° to find the other angle. If you know the angle which isn’t one of the two equal angles, take that away from 180° and then half your answer to find the other two (equal) angles
  • Look out for parallel lines. You can use corresponding angles and alternate angles with these
  • The exterior angles of a polygon add up to 360°. If you know that your polygon has equal sides then all its exterior angles will be the same, so divide 360° by the number of sides to work out the size of the exterior angle
  • The interior angles in a quadrilateral add up to 360°
  • Look out for circles and know the facts about angles in circles. Refer to the in-game maths help if you are unsure
  • If you see a triangle in which two of the sides are radii of a circle then it is an isosceles triangle, as those two sides will be equal.


  • When you start a new level, spend a few moments to spot its main mathematical features. Are there any triangles that will be useful? Any parallel lines? Any circles that will help you with your calculations?
  • Try to decide the best order in which to calculate the angles. Often you need to work out other angles in order to calculate the angles needed to remove lines.
  • Sometimes it helps to imagine extra lines in your diagram to solve problems.
  • You will need to remove some lines more than once. Remember that once you’ve correctly found an angle you can remove its line as often as you wish.
  • Sometimes it’s useful to rest Itzi against a line you can remove; then, when you remove it, Itzi will start rolling. Use this control to your advantage when timing is important.
  • As you progress through the game, you will need to use more and more facts about angles. Use the in-game maths help to find out what you need to progress.
  • Don’t assume that two lines are parallel or the same length unless they are marked as being so. It’s easy to think that because two lines look roughly the same length they are the same length. Likewise, it’s easy to think that two lines are parallel because they have roughly the same direction.
  • It’s always possible to complete a level without Itzi taking any damage – and it’s the only way to get A and S Ranks!
  • Getting an S Rank is tough... really tough! To earn them, you need to achieve or surpass the best scores of Mangahigh’s team of designers and testers. Not only do you need to be razor sharp on your maths, get ALL the flies and take NO damage, you also need to complete the level in a super-fast time. Look for shortcuts and tricks that will save you seconds, and be prepared to take risks!

Learn how to assign a game activity here.

How Did We Do?