Posted by **Mary** on Sunday, May 22, 2011 at 3:18pm.

How do I find the area of a trapazoid with side lenghts 6 & 7, bottom 17 and top 10.

I know the perimeter is 40.

Now I need the area.

- Geometry -
**Reiny**, Sunday, May 22, 2011 at 4:30pm
draw the trap ABCD where AD=10,DC = 7, BC=17 and BA = 6

Draw AE parallel to DC, then AE=7 and BE = 7

We now have a parallelogram and a triangle.

Let's find angle AEB which is also angle C , call it Ø

by cosine law in triangle ABE

6^2 = 7^2 + 7^2 - 2(7)(7)cosØ

cosØ = .632653

Ø = 50.75386°

area = triangle + parallelogram

= (1/2)(7)(7)sin 50.75386 + (10)(7)sin50.75386

= 73.184

## Answer this Question

## Related Questions

- calculus help lttle question - find the area of the regin bounded by the graphs ...
- Math - Find the Maximum area for the given perimeter of a rectangle. State the ...
- geometry - ok i have 2 problems and id appreciate it if someone can help :) 1. ...
- geometry - Find the length of a side of a square whose perimeter and area have ...
- geometry - in a triangle the middle length side is 3 more than the shortest side...
- geometry problems (algebra) - the lengths of the triangle are consecutive odd ...
- math grade 6 - give the demention of the rectangle with an area of 100 square ...
- math --- pls check my work! - help pls asap!!! Check my work! 1. Find the area ...
- geometry - what is the area of a trapazoid h=6,b1=5,b2=3
- Geometry - Find the area of a decagon with side of 4cm. Find the area of a ...