WHAT YOU NEED: two pieces of paper/card, pencil, scissors, ruler. Image caption, STEP 1: Place one piece of card on top of the other and use the ruler to draw a line from the bottom left corner of the ...

To calculate the area of a rectangle you multiply the length by the width. A right-angled triangle is like half a rectangle. So to calculate the area of a triangle, you can work out the area of the ...