Aballoon has a circumference of 11 cm. use the circumference to approximate the surface area of the balloon to the nearest square centimeter.

Name the most appropriate metric unit for each measurement

Is the square root of 4 plus the square root of 16 rational?

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.