Answer
$sin 90^{\circ}=\frac{\sqrt 3}{2}.\frac{\sqrt 3}{2}+\frac{1}{2}.\frac{1}{2}=1$
Work Step by Step
$sin (A+B) = sinA cosB + cosA sinB$
So, $sin(60^{\circ}+30^{\circ})=sin60^{\circ}cos30^{\circ}+cos60^{\circ}sin30^{\circ}$
So, $sin 90^{\circ}=\frac{\sqrt 3}{2}.\frac{\sqrt 3}{2}+\frac{1}{2}.\frac{1}{2}=1$
