What is the measure of angle a?

Mathematics

1 answer:

Mkey [24]3 years ago

8 0

Answer:

38°

Step-by-step explanation:

Using the Cosine rule in Δ ABC

cos A = $\frac{b^2+c^2-a^2}{2bc}$

where a, b and c are the sides of the triangle.

Here a = 5, b = 3 and c = 7 , thus

cos A = $\frac{3^2+7^2-5^2}{2(3)(7)}$ = $\frac{9+49-25}{42}$ = $\frac{33}{42}$ , thus

∠ A = $cos^{-1}$ ( $\frac{33}{42}$ ) ≈ 38°

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Step-by-step explanation: