Question

The following two triangles are similar.

a) What scale factor is applied to triangle A to create triangle B?

b) Find the values of x and y.

c) Are these right triangles?(yes or no)

Answer 1

Explanation:

all pairs of corresponding sides have the same scale factor.

so, we only need to find one to know it for all.

a)

we know 2 corresponding sides : 6 and 12.

that means

12 × s = 6

s = 6/12 = 1/2

b)

x = 5 × s = 5 × 1/2 = 2.5 = 2 1/2

y = 13 × s = 13 × 1/2 = 6.5 = 6 1/2

c)

to be right-angled triangles they need to fulfill the Pythagoras criteria :

c² = a² + b²

c is the Hypotenuse (the side opposite of the 90° angle).

a and b are the legs.

so, for the larger triangle we have

13² = 12² + 5²

169 = 144 + 25 = 169

correct. it is right-angled.

for the smaller triangle :

6.5² = 6² + 2.5²

42.25 = 36 + 6.25 = 42.25

as expected : also correct. so, yes, they are both right-angled.