Area of triangle PQR is 100 cm² (Fig. 9.20). If altitude QT is 10 cm, then its base PR is
a. 20 cm
b. 15 cm
c. 10 cm
d. 5 cm

Solution:

It is given that

Area of triangle PQR = 100 cm²

We know that

Area of triangle = 1/2 × base × height

Area of triangle PQR = 1/2 × PR × QT

Substituting the values

100 = 1/2 × PR × 10

By further calculation

PR = (100 × 2)/ 10

So we get

PR = 20 cm

Therefore, PR is 20 cm.

✦ Try This: 81 unit squares are joined to form a rectangle with the least perimeter. Perimeter of the rectangle is

☛ Also Check: NCERT Solutions for Class 7 Maths Chapter 11

NCERT Exemplar Class 7 Maths Chapter 9 Problem 15

Area of triangle PQR is 100 cm² (Fig. 9.20). If altitude QT is 10 cm, then its base PR is a. 20 cm, b. 15 cm, c. 10 cm, d. 5 cm

Summary:

Area of triangle PQR is 100 cm² (Fig. 9.20). If altitude QT is 10 cm, then its base PR is 20 cm

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