Question

In ΔPQR, PQ = 4 cm, QR = 3 cm, and RP = 3.5 cm. ΔDEF is similar to ΔPQR. If EF = 9 cm, what is the perimeter of ΔDEF?

A 10.5 cm Correct Answer Incorrect Answer
B 21 cm Correct Answer Incorrect Answer
C 31.5 cm Correct Answer Incorrect Answer
D None of these Correct Answer Incorrect Answer

Solution

Given, △ PQR ∼△ DEF ⇒ PQ/DE = QR/EF = RP/FD Since, PQ/DE = QR/EF ⇒ 4/DE = 3/9 ⇒ DE = 12 cm Similarly, QR/EF = RP/FD ⇒ 3/9 = 3.5/FD ⇒ FD = 10.5 cm ∴ Perimeter of △ DEF = DE + EF + FD = 12 + 9 + 10.5 = 31.5 cm

Practice Next
×
×