Two opposite sides of a square are increased by 5 cm to form a rectangle. If the rectangle has a perimeter of 70 cm, what was the length of a side of the original square?

  15 cm

Step-by-step explanation:

Adding 5 cm twice increased the perimeter to 70 cm, so it must have been 60 cm to start with.

A square with perimeter 60 cm will have a side length of (60 cm)/4 = 15 cm.

The side of the original square was 15 cm.

Check

The rectangle is 15 cm by 20 cm, so has a perimeter of 2(15 +20) = 70 cm.

square pyramid

step-by-step explanation:

square prism looks like nothing like that

triangular prism has a rectangular base instead of a square base

tetrahedron has a triangular base