Question

A triangle has sides A, B, and C. Sides A and B are of lengths `4` and `3`, respectively, and the angle between A and B is `(5pi)/12`. What is the length of side C?

Answer 1

`C=4.34`

Explanation:

As per law of cosines
`C^2=A^2+B^2-2Atimes Btimescos(theta)` where `A=4;B=3 and theta=(5pi)/12`
or
`C^2=4^2+3^2-2times4times3timescos((5pi)/12)`
or
`C^2=16+9-24times0.2588`
or
`C^2=25-6.2`
or
`C^2=18.8`
or
`C=sqrt18.8`
or
`C=4.34`