The edges of a triangular board are 6 cm, 8 cm and 10 cm respectively.

1.	The edges of a triangular board are 6 cm, 8 cm and 10 cm respectively. Find the cost of painting at the rate of Rs 9 per m2.
Answer» Semi-perimeter of a triangular board = \(\frac { 6+8+10 }{ 2 }\) = 12 cm Area of triangular board = \(\sqrt { 12(12-6)(12-8)(12-10) } \) = \(\sqrt { 12\times 6\times 4\times 2 } \) = 24 cm² Cost of painting 1 cm² is Rs 9 Cost of painting 24 cm² is 24 x 9 = Rs 216

The edges of a triangular board are 6 cm, 8 cm and 10 cm respectively. Find the cost of painting at the rate of Rs 9 per m2.

Answer»

Semi-perimeter of a triangular board

= \(\frac { 6+8+10 }{ 2 }\) = 12 cm

Area of triangular board

= \(\sqrt { 12(12-6)(12-8)(12-10) } \)

= \(\sqrt { 12\times 6\times 4\times 2 } \)

= 24 cm²

Cost of painting 1 cm² is Rs 9

Cost of painting 24 cm² is 24 x 9

= Rs 216