82.0k views
1 vote
ASAP Can someone help with this problems just I only need which formula do I used I just need for 4,5 and 6 just tell me the formulas for Law of Cosines

ASAP Can someone help with this problems just I only need which formula do I used-example-1

1 Answer

4 votes

Step-by-step explanation:

The formula for law of cosines is:


a^(2) = b^(2) + c^(2) - 2bc(cosA)

This is written at the top of your paper.

The angle is substituted where the capital A is. The side opposite to the angle is the angle name's lowercase. The two other sides are b and c.

Substitute all the information you know, then isolate the variable that you do not know.

When your formula is rearranged to look like this:


(a^(2) - b^(2) - c^(2))/(- 2bc) = (cosA)

Solve the left side and punch into your calculator:

cos⁻¹(left side) to find the angle A.

User Jesper Blad Jensen
by
8.3k points