Posted by **sam** on Wednesday, September 2, 2009 at 10:22pm.

How do I figure out the area and perimeter of a square if all I know is the cross (top left corner to bottom right corner) measurement? I have a square with the cross measurement of 8.5 (or 4 X sq root of 2, i rounded to 8.5). The square looks like it is cut in half to look like 2 triangles and in the corner of one triangle it says 45 degrees.

Please help me, I am so confused, is there a formula to figure this problem out?

- Geometry -
**MathMate**, Wednesday, September 2, 2009 at 10:48pm
The diagonal (the slant of the triangle) of a square of side x is √2*x.

Can you figure the side using this relation?

- Geometry -
**Reiny**, Wednesday, September 2, 2009 at 10:51pm
I don't know what grade level you are in, but since you seem to know about square roots, I am somewhat surprised that you don't know the Pythagorean Theorem.

Since you are dealing with a square, let each side of the square be x

then x^2 + x^2 = (4√2)^2

2x^2 = 32

x^2 = 16

x = 4

Now that we know that we have a 4 x 4 square, we can easily find its area and perimeter.

- Geometry -
**Reiny**, Wednesday, September 2, 2009 at 10:57pm
BTW, how did you come up with 8.5 for 4√2 ?

## Answer this Question

## Related Questions

- Physics 1112 Electric charge - As shown in the figure, a square has sides of 8.0...
- Physics - At each corner of a square of side script i there are point charges of...
- Math - I need help with this problem. (Just imagine a small square with 5x-1 at ...
- Calculus - You are given a 60 inch by 30 inch piece of cardboad and asked to ...
- algebra - There are two similar triangles. The angles are: from top to bottom ...
- Physics - I don't really know where to start on the problem. Would I use V = k(q...
- Physics - There are two particles of charge +Q located on the top left and ...
- geometry - I need help. One diagram backward Z, has 2|lines intersected by ...
- algebra - Area of a square find a polynominal A(X) that represents the area of ...
- Math - Really stuck on this question not sure where im going wrong a trapezium ...

More Related Questions