How to turn 7/20 into a decimal

Which of the following is the best first step in solving the equation below? 4+2㏒³x=17

At a pizza shop 70% of the customers order a pizza 25% of the customers order a salad and 15% of the customers order both a pizza and a salad if s customer is chosen at random what is the probability that he or she orders either a pizza or a salad

The area of each triangle is 7 square units. the surface area of the triangular prism is