If you know the diameter of a circle, how do you find its circumference? a) multiply the diameter by π. b) multiply the diameter by 2π. c) square the diameter and multiply by π. d) divide the diameter in half and multiply by π.

Acredit card advertises an annual interest rate of 23%. what is the equivalent monthly interest rate?

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.

Aliter of water contains about 3.35 x 10^25 molecules. a certain river discharges about 2.9x 10^8 l of water every second. about how many molecules does the river discharge every minute? write your answer in scientific notation