Question

Pls help, I know the answer but what I wrote in the box isn't correct

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Answer 1

AC=11.38 cm

Explanation:

The Law of Cosines

It relates the length of the sides of a triangle with one of its internal angles.

Let a,b, and c be the length of the sides of a given triangle, and x the included angle between sides a and b, then the following relation applies:

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

The figure shows two triangles and we are required to calculate the length of the side AC, knowing two sides and the angle between them. Thus, applying the formula:

`AC^2=17^2+13^2-2*17*13*\cos42^\circ`

`AC^2=289+169-442*0.7431`

`AC^2=129.53`

`AC=√(129.53)`

AC=11.38 cm