In a bag, 12 marbles are blue. this is 80% of the marbles. how many marbles are there in total?

What is the product of the radical expression. (7-2square root) (8+2 square root)

If you were constructing a triangular frame, and you had wood in the length of 4inches, 4 inches, and 7 inches, would it make a triangle? would you be able to create a frame from these pieces of wood? yes or no. explain your mathematical thinking

In a sale there is 25% of all prices a chair costs £45 in sale how much was it before the sale