Question

In △ABC, a=31, b=22, and c=18. Identify m∠A rounded to the nearest degree. HELP ME PLEASE!!

Answer 1

Answer:

The measure of angle A is $101\°$

Step-by-step explanation:

we know that

Applying the law of cosines

$a^{2} =b^{2}+c^{2}-2(b)(c)cos(A)$

substitute the values and solve for cos(A)

$31^{2} =22^{2}+18^{2}-2(22)(18)cos(A)$

$cos(A)=[22^{2}+18^{2}-31^{2}]/(2(22)(18))\\ \\cos(A)=-0.193182\\ \\A=arccos(-0.193182)=101\°$