Question

Triangle ABC has side lengths of a equals 15 three equals 15 square root three and C equals 30 inches part a determine the measure of angle be part B show how to use the unit circle to find Tandy part C calculate the area of triangle ABC

Answer 1

Answer:

∠B = 60°

Explanation:

Let us first draw the triangle.

Now the law of cosines gives

$(15\sqrt{3})^2=30^2+15^2-2(15*30)cosB$

which simplfies to give

$675=1125-900cosB$$\Rightarrow2\cos B=1$$\cos B=\frac{1}{2}$

Solving for B gives

$B=\cos^{-1}(\frac{1}{2})$

Using a calculator we get

$\boxed{B=60^o}$

which is our answer!