Question

$\triangle ABC \sim \triangle PQR$ such that ar($\triangle ABC$) = 4 ar($\triangle PQR$). If BC = 12 cm, then QR =
(a) 9 cm
(b) 10 cm
(c) 6 cm
(d) 8 cm

Answer 1

Answer:

The Length of QR is 6 cm .

Among the given options option (c) is 6 cm is the correct answer.

Step-by-step explanation:

Given:

ΔABC ~ ΔPQR.

ar(ΔABC) = 4 ar( ΔPQR)

BC  = 12 cm

ar(ΔABC)/ar( ΔPQR) = (BC/QR)²

[The ratio of area of two similar triangles is equal to the ratio of squares of their corresponding sides.]

4 ar( ΔPQR)/ar( ΔPQR) = (12/QR)²

√4/1 = (12/QR)

2/1 = 12/QR

2 QR = 12

QR = 12/2

QR = 6 cm

Hence, the Length of QR is 6 cm

HOPE THIS ANSWER WILL HELP YOU ..

Answer 2

$\triangle ABC \sim \triangle PQR$ such that ar($\triangle ABC$) = 4 ar($\triangle PQR$). If BC = 12 cm, then QR =

(a) 9 cm

(b) 10 cm

(c) 6 cm✔✔

(d) 8 cm