# Area of triangles

CCSS Math: 6.G.A.1

Intuition for why the area of a triangle is one half of base times height.

## Intuition for why the area of a triangle is $A=\dfrac{1}{2}bh$

To see why the formula makes sense,

**drag the dot all the way to the right:**Whoa! You made a rectangle that's twice as big as the triangle! The area of the rectangle is $bh=4\times 5 = 20$ square units, so the area of the triangle is $\dfrac 12 bh = \dfrac 12 \times 4 \times 5 = 10$ square units.

**Key intuition:**A triangle is half as big as the rectangle that surrounds it, which is why the area of a triangle is one-half base times height.