Expert: Michael Hartley - 9/25/2006

Question
Please explain to me how you figure out square footage on a triangle. example the bottom line is 9 and from the bottom line to the tip is 3ft. What is the equation on figuring this out

Answer
The equation is

AREA = ONE HALF times BASE times HEIGHT

The BASE is the length of the bottom line.

The HEIGHT is the 'straight up' distance from the (horizontal) bottom line to the tip.

And ONE HALF is, well, one half.

So if your triangle had a bottom line of length 5 ft, and a height of 7 ft, the area would be

1/2 times 5 times 7, that is, 35/2 or 17.5 square feet.

You should be able to figure out the answer to your example now...

By the way did you know that a similar formula works to find the volume of a pyramid?

If BASE is the AREA of the base of the pyramid, and HEIGHT is the height of the tip of the pyramid above the base, then

VOLUME = ONE THIRD times BASE times HEIGHT

And this works not just for pyramids, but also for cones...