Question

Draw two rectangles on the squared paper with different dimensions that have an area of 18 square units. Mark each rectangle to create a triangle with an area of 9 square units.

Answer 1

Here are some possible dimensions for a rectangle that has area 18 square units:

• 1 by 18
• 2 by 9
• 3 by 6

There are infinitely many other combos, but those are the only three such that each side is a whole number.

To form the triangle we need, place the base of the triangle along one of the sides of the rectangle. Place the third vertex of the triangle along the opposite side of the rectangle. It can be anywhere along the opposite side. This triangle will have the same base and height as the rectangle, but it will have half the area.

This is because:

• area of rectangle = base*height
• area of triangle = 0.5*base*height = 0.5*(area of rectangle)