Question

Determine the unknown angle measures of ADEF.Round to the nearest degree.m2D23.5m2 =24.3D33.8F

Answer 1

Given:

The sides of the triangle ABC are given

a=7, c= 8 and b= 13.

To find

The angle C.

Step-by-step explanation:

To find angle C , use the cosine rule.

`c^2=a^2+b^2-2ab\cos C`

Substitute the values in the cosine rule.

`8^2=7^2+13^2-2*7*13\cos C`
`64=49+169-182cosC`
`182\cos C=49+169-64`
`182\cos C=154`
`\cos C=(154)/(182)`
`C=\cos ^(-1)(0.846)=32.2^(\circ)`

Answer :

Hence the angle C is obtained as 32.2 degree.