A square has an area of 81 cm2.
Find the perimeter of the square

Cora bought a package of erasers. there are 4 pink erasers and 12 blue erasers. what is the ratio of pink erasers to blue erasers?

Fanny mendelssohn manages all the magazines and paperback books at a local grocery store. she prices many paperbacks to sell at $7.99. the cost to the store is $5.29. what is the markup rate on a paperback book, based on its cost?

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?