Question

Round to the nearest tenth (picture provided)

Answer 1

d. 6.3

Explanation:

Given
`b=3,c=9` and
`A=21\degree`, we can use the cosine rule to find
`a`.

The cosine rule is given by;

`a^2=b^2+c^2-2bc\cos(A)`

We substitute the values to obtain;

`a^2=3^2+9^2-2(3)(9)\cos(21\degree)`

`a^2=9+81-54\cos(21\degree)`

`a^2=90-50.4133`

`a^2=39.5867`

`a=√(39.5867)`

`a=6.2918`

To the nearest tenth,
`a=6.3`