Question

Find A in degrees. Round to the nearest tenth.
a=7
b=4
c=8

A=[?]°​

Answer 1

Answer: 61 degrees

Explanation:

7^2=4^2+8^2-2(4)(8)cos a

7^2-4^2-8^2/-2(4)(8)=.434

Then do the inverse cosine of .434, and it will equal to 61.02

Round to the nearest tenth and you'll get A= 61 degrees.

Answer 2

61 degrees.

Explanation:

Use the law of cosine.

In this case, the law of cosine is:

7^2=4^2+8^2-2(4)(8)cos a

Meaning:

7^2-4^2-8^2/-2(4)(8)=.434

Then do the inverse cosine of .434, and it will equal to 61.02

Round to the nearest tenth and you'll get A= 61 degrees.