1. Write a formula that expresses the radius r of a circle as a function of its diameter d. 2. Write a formula that expresses the diameter d of a circle as a function of its radius r. 3. If $51.30 in...

1. Write a formula that expresses the radius r of a circle as a function of its diameter d.

2. Write a formula that expresses the diameter d of a circle as a function of its radius r.

3. If $51.30 in interest is earned on a deposit of $950 in one year, then what is the simple interest rate?