Im not quite sure how to solve this.

For what is the measure of the angle at the top of the shed? a. multiplication of areas b. squaring of areas c. addition of areas d. division of areas

Convert 2000 swiss francs to dutch guilders

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.