# Find Exact Value without Calculator

• July 11th 2011, 03:14 AM
DamenFaltor
Find Exact Value without Calculator
Hello all,

I'm trying to determine how one would solve the below problem without a calculator or a table. None of the angles are ones I easily recognize - how can I solve it?

These are given in degrees, not Rads

$sin(81 + 21)$

Thank you for all of your brilliant help!(Bow)
• July 11th 2011, 03:26 AM
Prove It
Re: Find Exact Value without Calculator
\displaystyle \begin{align*}\sin{\left(102^{\circ}\right)} &= \sin{\left(6^{\circ} + 36^{\circ} + 60^{\circ}\right)}\end{align*}

You will need to use the angle sum identity at least twice. Also Exact trigonometric constants - Wikipedia, the free encyclopedia will help you.