http://media.careerlauncher.com.s3.amazonaws.com/gate/material/7.pdf

take a look at page 6

how did he get the y-20 / x = 60-20 / 10

i cant see the proportions with so many lines in the way witht eh same lineweigth

and why is the area = 20(2y)

area of rectangle is simply l*w
20 is thickness , constant
2 is a factor since the beam is centered midline, they use y being one half of the dimension
y is the height dimension, centerline to outside

y, height , was modeked by x position. simply write down 2 ordered pairs describing end and beginnning and solve the line connecting them. treat 1 end to be x=0

This post was edited by saber_x3 on Jan 17 2014 02:19am

Isn't it 20 - y? Because 20 is longer then y?