Question

find m∠A.

Answer 1

plz help

Answer 2

You can use the formula a^2=c^2+b^2-2abcosA, just put your values in for a,b and c and solve for A

Answer 3

can you help me plug them in ... im really confused :(

Answer 4

So a=4, b=5 and c=2

Answer 5

4^2=(5^2)+(2^2)-2(5)(2)cosA
I realized in the second portion it should have been bc not ab

Answer 6

16=25+4-20cosA
16=29-20cosA
-13=-20cosA
0.65=cosA
A=? Are you able to finish that?

Answer 7

would divide 0.64 by cosA? if it is right im not really sure how to solve it

Answer 8

Nope you have to do the inverse of the cosine function in order to get A by itself so:
\[\cos ^{-1}(0.65)\]

Answer 9

ohh... i know im gonna sound kinda dumb.. but how do you do the inverse?

Answer 10

i dont mean to sound mean but can you give me the answer i only have couple of mins left ! im on a timed quiz

Answer 11

It's 49.46

Answer 12

thank you so much taramgrant ! really appreciate it :) :)

Answer 13

No problem!