Question

What is the are of a triangle (picture provided)

Answer 1

Area Δ = 102.3 units² ⇒ The answer is (d)

Explanation:

Use the formula of the area:

∵ Area of the triangle = 1/2 (a)(b) sin(C)

∵ We have the length of the 3 sides

∴ Use cos Rule to find the angle C

∵ cos(C) = (a² + b² - c²)/2ab

∵ a = 25 , b = 13 , c = 17

∴ cos(C) = (25² + 13² - 17²)/2(25)(13) = 625 + 169 - 289/650 = 505/650

∴ m∠C = 39°

∴ Area Δ = (1/2)(25)(13)sin(39) = 102.3 units²

∴ The answer is (d)

Answer 2

Area Δ = 102.3 units² ⇒ The answer is (d)

Explanation:

* Use the formula of the area:

∵ Area of the triangle = 1/2 (a)(b) sin(C)

∵ We have the length of the 3 sides

∴ Use cos Rule to find the angle C

∵ cos(C) = (a² + b² - c²)/2ab

∵ a = 25 , b = 13 , c = 17

∴ cos(C) = (25² + 13² - 17²)/2(25)(13) = 625 + 169 - 289/650 = 505/650

∴ m∠C = 39°

∴ Area Δ = (1/2)(25)(13)sin(39) = 102.3 units²

∴ The answer is (d)