The area of a triangle is 45cm2 and the height is 9 cm. what is the length of the base?

Formula
A=bh divides by 2

SUBSTITUTE
45=b9 divided by 2

MULTIPLY/DIVIDE

You can either divide by 2 or multiply by 1/2 (gets the same answer)
9 x 1/2 = 4.5

DIVIDE
45 divides by 4.5 = 10

CHECK

A= 10 x 9 divided by 2 or multiply by 1/2 (same answer) = 45

Thus, the answer is 10.
I hope this helped you understand the process!