Author Topic: One more Geometry Question (Read 275 times)

Yeager · « **on:** June 11, 2007, 12:19:47 AM »

Then I'm out for the night:

I have an Equilateral Triangle that is One meter wide at the bass and 0.866 Meters high at the apex.

What is the Area?

What is the Perimeter?

rpm · « **Reply #1 on:** June 11, 2007, 12:37:53 AM »

The perimeter of the base is 4 meters. That's all I can answer in this alcohol induced haze.

fd ski · « **Reply #2 on:** June 11, 2007, 01:09:37 AM »

you're joking, right ?

rpm · « **Reply #3 on:** June 11, 2007, 01:14:34 AM »

I wasn't expecting a geometry pop quiz mid buzz.

CFYA · « **Reply #4 on:** June 11, 2007, 01:52:26 AM »

Area is .433 sq meters or 433 sq centimeters

(Height X Width)/2 is the correct formula for area for most(I believe all) triangles.

The formula for perimeter escapes me at this hour in the morning.

~~CFYA~~

Bluedog · « **Reply #5 on:** June 11, 2007, 01:59:03 AM »

formula for perimeter of an equilateral triangle would be side x 3

CFYA · « **Reply #6 on:** June 11, 2007, 01:59:17 AM »

Duh.....I am to tired but it just hit me.

Equilateral triangle is defined as a triangle have 3 equal length sides.

Your base dimension is 1 therefor your two other sides are also 1 meter long.

Perimeter is 3.

Edit:Yeah it me like a load of bricks soon as I thought about it for a few minutes. Was thinking of right or scalene triangle some how. Its 3 am here...

~~CFYA~~

Samiam · « **Reply #7 on:** June 11, 2007, 01:24:28 PM »

Area for a right triangle is 1/2 x base x height (half a rectangle).

In the case of an equilateral triangle, you can bisect it into two identical right triangles, and therefore the area of the original triangle is simply base x height.

In this case that's just .866m(sq)

lasersailor184 · « **Reply #8 on:** June 11, 2007, 02:12:12 PM »

Quote

Originally posted by Samiam
Area for a right triangle is 1/2 x base x height (half a rectangle).

In the case of an equilateral triangle, you can bisect it into two identical right triangles, and therefore the area of the original triangle is simply base x height.

In this case that's just .866m(sq)

Wrong.

The thinking behind multiplying HALF the base, times the height is that you can break off a portion of the triangle, and then rearrange it to create a rectangle.

Your equation is faulty, because you are effectively doubling the area. You break off half of the triangle, and then FORGET to remove that value from the base multiplication.

mietla · « **Reply #9 on:** June 11, 2007, 02:36:23 PM »

I just love the diversity of opinions on what the area of a triangle is.

Only in (diverse) America.

Maybe we should let congress decide what the answer should be, so no cultural bias will show and no one will get offended in a process.

Engine · « **Reply #10 on:** June 11, 2007, 03:26:06 PM »

I'm offended by that.

Samiam · « **Reply #11 on:** June 11, 2007, 03:32:35 PM »

Doh! You are correct laser. When you bisect the triangle, the base of each right triangle is half the width of the original triangle, so it is, indeed .433sq. m.