Math Help -.-..I'm stuck geometry question

Nor · 03-28-2008, 03:47 PM

I tried splitting up the image into 3 parts, 2triangles, retangle, and tried doing the Pytagorean Theorem on the triangle, no luck because each triangles base can't be 5 since it isn't a isosceles trapezoid. My teacher had problems with it in the teacher manual said they split it into a parallelogram and a triangle, but I still won't get the height of the triangle because I can't define if its a isosceles triangle.

If you figure it out mind explaning.

The real question is find the area, I got the area from teacher but she wants to know how to find the height, got me confused -.-...

martins256 · 03-28-2008, 05:15 PM

Sorry for my bad English ;)
the line that is || the side of length 6 is right. the triangles bottom sides length is 10 (32-22=10)

So you get a triangle with sides 6 8 10 these numbers are specific for a triangle with 90*. to get the height u firstly need to get the triangles square. square = 6*8/2.
And finally the height = 2*square/a . Where a = 10.
If the triangle you got is without the 90* corner then the formula for its square is S=sqrt(p(p-a)(p-b)(p-c)) the formula is called Heron formula. And p = (a+b+c)/2 a,b,c are the sides of the triangle

Nor · 03-28-2008, 09:59 PM

Thanks, but if the total area of the complete trapizoid is 129.65(something) how is this possible? teacher handbook said thats what total area is.

Heres my work:

square of triangle(sot) = a*b/2
sot = 6*8/2
sot = 48/2
sot = 24

height = 2*square/a
height = 2*24/6
height = 48/6
height = 8

trapizoid area(ta) = (h(b1+b2))/2
ta = 8(22+32) / 2
ta = 8*52 / 2
ta = 416 / 2
ta = 208 units squared

martins256 · 03-28-2008, 10:54 PM

square of triangle(sot) = a*b/2
sot = 6*8/2
sot = 48/2
sot = 24

//a is the side of triangle to which the height is pointing
// if you imagine a triangle ABC and the height is A to a point on BC then BC is that "a"
height = 2*square/a
height = 2*24/10
height = 48/10
height = 4.8

trapizoid area(ta) = (h(b1+b2))/2
ta = 4.8(22+32) / 2
ta = 4.8*54 / 2
ta = 259.2 / 2
ta = 129.6 units squared

Nor · 03-28-2008, 11:05 PM

OHHH DUDE XD NICE, I used 8 instead of 10, and some other bugz :P :$ wow your a life savor, going to show off to my teacher monday :)