Math Module 1 Question 19

In an isosceles triangle

A B C

c o s (A) = \frac{12}{13}

and

c o s (B) = - 0.70

. What is the value of

s i n (C)

in simplified fraction?

Answer:

Answer:

5/13

Explanation

The correct answer is $\frac{5}{13}$

Draw a diagram for the right-angled triangle as described in the question and then find $s i n (C)$ .

An angle is greater than $90 °$ and less than $270 °$ when the cosine of the angle is negative, based on unit circle trigonometry.

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