Area: Triangle vs. Rectangle
Date: 4/30/96 at 12:2:36 From: Anonymous Subject: Math Dear Dr.Math, Why do you have to use a different formula to get the area of a triangle than a rectangle or square?
Date: 5/4/96 at 16:54:44 From: Doctor Mike Subject: Re: Math Greetings, You use a different formula because it is a different problem. The answer is different so you need a different process to get the answer. There is another way to explain this with a picture. Here is a rectangle with a line drawn from one corner to the opposite corner: ------------ |\ | | \ | | \ | | \ | | \ | | \ | | \ | | \ | | \ | | \| ------------ The rectangle is about 2 cm wide and 4 cm tall, so its area is 2 times 4 , which is 8 square cm. Clearly, the rectangle is made up of the 2 triangles. If you used the same formula to get the area of the triangles you would get the wrong answer. Each triangle is one half the area of the whole rectangle. You get that if you use the correct formula for the area of the trangle, which is "Base times Altitude times 1/2". I hope that was clear. If you have any more questions please write us again. -Doctor Mike, The Math Forum Check out our web site! http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.