In δabc, if the length of sides a, b, and c are 3.5 centimeters, 5.5 centimeters, and 6 centimeters respectively, what is m∠c to two decimal places?

We start by sketching the triangle ABC as shown below. We label the side with the small letters a,b, and c on the opposite of the angle A, B, and C

The angle m<C is labeled x

To work out the size of x, we use the cosine rule







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