Question

the sides of the triangular base of a prism are 13 cm ,20cm and 21 cm find the area of its cross section

Answer 1

126sq cm

Explanation:

Let s be the semi-perimeter of the triangular base of the prism. Then,

S = (13 + 20 + 21)/2 cm. = 27 cm.

Therefore, the area of the prism = √[s(s - a)(s - b)(s - c)]

= √(27(27 - 13)(27 - 20)(27 - 21)) sq. cm.

= √(27 × 14 × 7 × 6) sq. cm.

= 9 × 7 × 2 sq. cm.

= 63 *2

=126sq cm

Hope this helps!!!