Geometrical shapes with an unknown

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SUMMARY

The discussion centers on solving a geometry problem involving a rectangle ABCD, a square EFGD, and a right triangle BMF. Given the dimensions DC = 60 cm and BC = 40 cm, the combined area of the square and triangle is 784 cm². The user derived the quadratic equation 3x² - 100x + 832 = 0 to find the unknown variable x, but encountered errors in calculations. The user acknowledged a mistake in their approach, leading to incorrect figures.

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Homework Statement




http://img857.imageshack.us/img857/3200/thedrawing00.jpg


In a rectangle ABCD a square is built, EFGD, and a right triangle BMF, as described in the drawing.
Given:
DC = 60 cm
BC = 40 cm
The sum of the area of the square and the triangle is 784 cm2

Calculate x (find both answers).


The Attempt at a Solution



I built the equation of their area using x. As I solve the final quadratic am not getting the right figures from some reason.

http://img709.imageshack.us/img709/7970/areaxx1.jpg
 
Last edited by a moderator:
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Ok: I work it out to 3x^2 - 100x + 832 = 0. I think you just let -x times -x = -x^2 for some reason.
 
Last edited:
Thanks, yes :) Just made a silly mistake *slaps forehead*

Much appreciated.
 

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