Question

Triangles PQR and STU are similar. The length of PQ = 36 cm, RP = 48 cm and QR = 24

cm. THe length of the longest side of triangle STU is 92 cm. What is the perimeter of
triangle STU?

Answer 1

207 cm

Explanation:

Because ΔPQR ≅ΔSTU and the longest side in the ΔPQR is RP then the longest side in ΔSTU must be SU = 92 cm

Perimeter of triangle PQR is

P(ΔPQR) = 36+48+24 = 108 cm

Because the triangles are are similar their sides are in proportion.

But how much bigger did the second triangle get?...is (92/48) times bigger

P(ΔSTU) = 180*(92/48) = 207 cm

...you can also use proportions to find each side and then find the perimeter

TU = 24*92 /48 = 46

TS = 36*92/48 = 69

SU = 92

P(ΔSTU) = 92+69+46 =207 cm

*the triangles are not drawn to scale