How do you calculate the area of a triangle e.g: Base:4 height:8 area?

4 Answers

Maria Not Telling Profile
The formula is a= 1/2bxh so 1/2(4)x8= 2x8=16 so the area is 16
thanked the writer.
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Jack TheJaxter
Jack TheJaxter commented
But that big rectangle's width is the same as the triangle's width (their corners meet, right?). And its height is the same as the triangle's height. And it's area is its width (same as the base of the triangle) x its height (same as the height of the triangle). Now we're ready to figure out the area of the triangle.
Jack TheJaxter
Jack TheJaxter commented
Remember how for each of the original rectangles, exactly half of that rectangle was covered by a portion of the triangle? That means that the area of the left portion of the triangle is 1/2 of the left rectangle's area, and the area of the right portion is 1/2 of the right rectangle's area.
Jack TheJaxter
Jack TheJaxter commented
We could work out the left rectangle's area, and divide by two, and then do the same for the right rectangle, and sum them, but there's a simpler way: Use the big rectangle's area (the same as the two little guys put together). We have to divide it by 2, since each rectangle was only half-covered by the triangle, and the other half is extra. So, the area of the triangle is 1/2 of the area of the big rectangle, or base x height. Formula: A = 1/2 x base x height. Cool, right?
tiffany james Profile
tiffany james answered
You multiply the base and height. Then divide the answer by 2.

(bh)/2  or    1/2(bh)

so it would be 8*4 = 32 then ÷ 2 = 16
Mandy Clark Profile
Mandy Clark answered
The formula is bh/2, base times height divided by 2. So you would do

8*4/2. You get 16 out of this:)
Jack TheJaxter Profile
Jack TheJaxter answered
See my comments to Maria Not Telling's answer. You won't remember the formula unless you understand why it works, so I explain it.  Use bits of paper, if it's easier to visualize what we're doing.

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