You are given two sides of a triangle, a = 4.5 and b = 6, the angle between them is 35 degrees, how do you find the third side and the area of the triangle.?

1 Answer
Aug 1, 2018

Third side is 3.47 unit and area of triangle is 7.74 sq.unit.

Explanation:

Sides a=4.5 , b=6 and their included angle /_C = 35^0

Cosine rule: (for all triangles) c^2=a^2 + b^2 − 2 a b cos(C)

:. c^2=4.5^2 + 6^2 − 2*4.5*6*cos(35) or

c^2~~12.02 :. c ~~ 3.47 (2dp)

Sides a=4.5 , b=6 and their included angle

/_C = 35^0. Area of the triangle is A_t=(a*b*sin C)/2

:.A_t=(4.5*6*sin 35)/2 ~~ 7.74 sq.unit

Area of the triangle is 7.74 sq.unit.

Third side is 3.47 unit and area of triangle is 7.74 sq.unit

[Ans]