Question

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Answer 1

Using the law of cosines, it is found that the length of side AB is of AB = 13.

What is the law of cosines?

The law of cosines states that we can find the angle C of a triangle as follows:

$c^2 = a^2 + b^2 - 2ab\cos{C}$

in which:

• c is the length of the side opposite to angle C.

• a and b are the lengths of the other sides.

For this problem, the parameters are:

C = 120, a = 8, b = 7.

Hence:

$c^2 = a^2 + b^2 - 2ab\cos{C}$

$c^2 = 8^2 + 7^2 - 2(8)(7)\cos{120^\circ}$

$c^2 = 169$

$c = \sqrt{169}$

c = 13.

Hence AB = 13.

More can be learned about the law of cosines at brainly.com/question/2491835

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