How do we calculate the circumference of a circle

Which expression can be added to the right side of the equal sign to form an equation?

Circle the common factors of 16a and 20ab. 2, 2a, 4ab, 4 a, 8b, 4a, 12b A. 2, 4, 2a; 4a B. 4a; 2,4

Which one has two zeros and two fours?

The product of two consecutive integers is 42. What are they?

The briarwood middle school chess club has 55 members. 22 of the percent of the members are 7th graders. what percent of the members of the chess club are 7th graders?

A newspaper reporter wants to know how popular the hobby of bird watching is in the city. He asked people at the local bird refuge if they watched birds as a hobby. Which of the following best explains whether the reporters data is valid or not?

I am very confused on how to figure out if y = 3/4x is proportional?

Alison wants to buy a mountain bike for $339.12. If she saves $28.26 each month, in how many months will she be able to buy the bike?

At 12 o'clock the temperature was 7°C. The temperature decreased by - 20°C. What is the new temperature?

Ashleys rentals charges $27.50 per hour to rent a surfboard and a wetsuit. Darlas surf shop charges $23.25 per hour to rent a surfboard plus $17 extra for a wetsuit.