Question

I want a way to solve this question​

Answer 1

Answer:

d

Step-by-step explanation:

Using the Cosine rule to find ∠ A

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

         = $\frac{5.1^2+5.7^2-7.3^2}{2(5.1)(5.7)}$

         = $\frac{26.01+32.49-53.29}{58.14}$

         = $\frac{5.21}{58.14}$ , then

∠ A = $cos^{-1}$ ( $\frac{5.21}{58.14}$ ) ≈ 84.9° ( to 1 dec. place )