Hurry plz i need help

Write a numerical expression that satisfies all of the following conditions. 1.)the only number used in the expression is 5 2.)at least one exponent other than 1 is used 3.)when the expression is evaluated, the answer is greater than 40 and less than 50

How do you find the circumfrance of a circle?

2.5 milligrams is equivalent to how many grams