Area of a Triangle
\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}Transcript
Today we find the area of any triangle using one simple formula. Let's start with a rectangle. It has length and width. A rectangle with length 6 and width 4 has area 24 square units.
Now here's the key: a triangle is exactly half of a rectangle. If we draw a diagonal line across the rectangle, we cut it in half. So the triangle's area is half the rectangle's area.
\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}For our triangle with base 6 and height 4, the area is half of 24. Let me show you another triangle with base 8 and height 5. Using our formula: area equals one half times 8 times 5.
- Area = 1/2 × 6 × 4 = 12
\text{Area} = \frac{1}{2} \times 8 \times 5 = 20The height must be perpendicular to the base, like a straight line down. Now you try: if a triangle has base 10 and height 6, what is its area? Remember: triangle area is always half of base times height.
- Height is perpendicular to base
Quick quiz
Q1. Triangle with base 10 and height 6: what is the area?
Area = 1/2 × 10 × 6 = 30 square units.
