How do you work out the area of a triangle?Area of a triangleTo calculate the area of a triangle, multiply the height by the width (this is also known as the 'base') then divide by 2.Find the area of a triangle where height = 5 cm and width = 8 cm.5 × 8 = 40 ÷ 2 = 20The area is 20cm².A triangle is always half the area of a rectangle with the same height and width.Start activityJavaScript is required to view this activity.Start activityJavaScript is required to view this activity.