$$(sin{60}^o)(cos{30}^o)(sin{30}^o)(cos{60}^o)=?$$

As we know that

$$sin{60}^o=\frac{\sqrt{3}}{2},cos{30}^o=\frac{\sqrt{3}}{2},sin{30}^o=\frac{1}{2},cos{60}^o=\frac{1}{2}$$

So, let's plug the values into the given equation

$$(sin{60}^o)(cos{30}^o)(sin{30}^o)(cos{60}^o)=\left(\frac{\sqrt{3}}{2}\right)\left(\frac{\sqrt{3}}{2}\right)+\left(\frac{1}{2}\right)\left(\frac{1}{2}\right)$$

$$=\frac{3}{4}+\frac{1}{4}$$

$$=\frac{3+1}{4}$$

$$=1$$

Also, we can see that

$$sin({60}^o+{30}^o)=sin{90}^o=1$$