Question

The sides of the triangular Base prism are 13cm,20cm and 21cm, find the area of it's cross section.

Plz don't ans if u Don't know@

Answer 1

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. 

Answer 2

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

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