Triangle Area

Area is half base times height, written $\frac{1}{2}bh$. For a triangle with base 10 cm and height 6 cm, the area is 0.5 * 10 * 6 = 30 sq cm. The height must be perpendicular to the chosen base.

Slide the base b and height h between 1 and 30 cm. The lab shows the area and also the rectangle area b*h for comparison. A triangle always has half the area of the matching rectangle, which the lab makes obvious.

Measure the base and the straight-up height in cm. If the base is 12 cm and height is 8 cm, the dosa half is 0.5 * 12 * 8 = 48 sq cm. The lab lets you check this kind of food-shape calculation in a few seconds.

Any triangle fits exactly inside a rectangle of the same base and height, taking up half of it. That is why we multiply by 0.5. The lab displays b*h next to 0.5*b*h so you can see the rectangle is always double the triangle, no matter the slider values.