Mathematics

The key is recognizing that $15°$ isn't a "standard" angle, but it is the difference of two that are: $45° - 30°$. Use the angle subtraction formula for sine to find $\sin 15°$, then square the result. Alternatively, you could use the half-angle formula since $15° = 30°/2$, which directly gives you $\sin^2 15°$ without an extra squaring step.

The key is recognizing that $15°$ isn't a "standard" angle, but it is the difference of two that are: $45° - 30°$. Use the angle subtraction formula for sine to find $\sin 15°$, then square the result. Alternatively, you could use the half-angle formula since $15° = 30°/2$, which directly gives you $\sin^2 15°$ without an extra squaring step.