Question

Please help! will give a medal!!!
What is the value of c, correct to one decimal place?

A.4.6
B.3.2
C.2.8
D.1.2

Answer 1

is one of those angles known? for example, is A a right angle?

Answer 2

angle C is 24.63

Answer 3

really? damn
now we have to go with the law of cosines

Answer 4

actually not too bad in this case
\[c^2=a^2+b^2-2ab\cos(C)\] is what you need

Answer 5

therefore
\[c^2=5^2+7^2-2\times 5\times 7\cos(24.63)\] and a calculator will get \(c^2\)
take the square root to get \(c\)

Answer 6

its giving me 10.36873858

Answer 7

the square root is 3.2