Question

In triangle ABC, a = 3, b = 5, and c = 7. Find the measure of B.



22°

38°

142°

158°

Answer 1

@perl

Answer 2

this is better
http://www.mathwarehouse.com/triangle-calculator/online.php

Answer 3

but itsn't that cheating?

Answer 4

its a way to check ?

Answer 5

no u can use calculators at school

Answer 6

so its 38?

Answer 7

side A is opposite angle A

Answer 8

yes

Answer 9

thnx

Answer 10

you can use law of cosines by the way to solve this problem

Answer 11

ok thnx

Answer 12

a = 3, b = 5, and c = 7.

we want angle B , which is between sides a and c

3^2 + 7^2 - 2*3*7*cos(theta) = 5^2

solve for theta

cos(theta) = (5^2 - 3^2 - 7^2)/(-2*3*7)

theta = arcos(5^2 - 3^2 - 7^2)/(-2*3*7)

theta = 38.2132