Question

calculate cosine to two decimal places

Answer 1

Answer:

Final answer is approx -0.07.

Step-by-step explanation:

We have been given a picture of the triangle whose sides are 7, 8 and 11.

Apply cosine formula to find the value of $\cos\left(\theta\right)$.

$a^2=b^2+c^2-2\cdot b\cdot c\cdot\cos\left(a\right)$

$11^2=7^2+8^2-2\cdot 7\cdot 8\cdot\cos\left(\theta\right)$

$121=49+64-112\cdot\cos\left(\theta\right)$

$121=113-112\cdot\cos\left(\theta\right)$

$121-113=-112\cdot\cos\left(\theta\right)$

$8=-112\cdot\cos\left(\theta\right)$

$\frac{8}{-112}=\cos\left(\theta\right)$

$-0.0714285714286=\cos\left(\theta\right)$

Hence final answer is approx -0.07.

Answer 2

The answer is C. -0.07.