Sad Man and the animals sing a sad song about the different sorts of triangles. They are having fun until Decimole demolishes all the triangles. In the Great Hall, the contestants have to make different triangles from lines on a screen. Sad Man reappears and demonstrates how to make an equilateral triangle from A4 paper. Bad Man startles some passers-by in a park by asking them if they have seen any escaped triangles. The triangles sing their catchy song. In the Great Hall, the contestants construct a right-angled triangle and a scalene triangle and so win the last maths card they need to escape from Maths Mansion.

Viewers' Challenge

If you connect up the outside points of each letter on a computer keyboard, how many of each of the following triangles can you find?

• equilateral
• 
  
• isosceles
• 
  
• scalene
• 
  
• right-angled
• 
  How many letters have no triangles?

Answers

Click on a letter below to choose an answer.

	Equilateral triangles: 2 -X(2) Isosceles triangles: 10 - W(3), T(1), Y(2), A(2), F(1), M(1) Scalene triangles: 1 - K Right-angled triangles: 10 - T(2), K(1), L(1), Z(2), N(2), M(2) Isosceles right-angled triangles: 5 - T(2), X(2), V(1) No triangles: 14 - Q, E, R, U, I, O, P, S, D, G H, J, C, B
	Equilateral triangles: 3 - Y(1), X(2) Isosceles triangles: 8 - W(3), T(1), Y(2), A(2) Scalene triangles: 1 - K Right-angled triangles: 10 - T(2), K(1), L(1), Z(2), N(2), M(2) Isosceles right-angled triangles: 5 - T(2), X(2), V(1) No triangles: 14 - Q, E, R, U, I, O, P, S, D, G H, J, C, B
	Equilateral triangles: 3 - Y(1), X(2) Isosceles triangles: 10 - W(3), T(1), Y(2), A(2), F(1), M(1) Scalene triangles: 1 - K Right-angled triangles: 10 - T(2), K(1), L(1), Z(2), N(2), M(2) Isosceles right-angled triangles: 5 - T(2), X(2), V(1) No triangles: 14 - Q, E, R, U, I, O, P, S, D, G H, J, C, B
	Equilateral triangles: 3 - Y(1), X(2) Isosceles triangles: 10 - W(3), T(1), Y(2), A(2), F(1), M(1) Scalene triangles: 1 - K Right-angled triangles: 8 - T(2), K(1), L(1), Z(2), N(2) Isosceles right-angled triangles: 5 - T(2), X(2), V(1) No triangles: 14 - Q, E, R, U, I, O, P, S, D, G H, J, C, B
	Equilateral triangles: 3 - Y(1), X(2) Isosceles triangles: 10 - W(3), T(1), Y(2), A(2), F(1), M(1) Scalene triangles: 1 - K Right-angled triangles: 10 - T(2), K(1), L(1), Z(2), N(2), M(2) Isosceles right-angled triangles: 5 - T(2), X(2), V(1) No triangles: 12 - Q, E, R, U, I, O, P, S, D, G H, J