Posted by Amanda on Tuesday, March 25, 2008 at 7:34pm.
The base length of each squarebased prism in the pedestal design is 3cm less than that of the layer immediately below.
a) Write an algebraic expression for the total of the top surface areas of the three prisms used to make the pedestal.
x
x
x
2x+5
2x+5
Please help, i am so stuck.

Math, please please help  PsyDAG, Wednesday, March 26, 2008 at 12:01pm
The surface area for each square would be the side multiplied by itself, with the bottom square = x^2.
The second square's surface would be (x3)^2.
From this, you should be able to determine how to calculate the third square's area.
Then sum these three terms.
I hope this helps. Thanks for asking. 
math  sydney, Thursday, May 26, 2011 at 10:06pm
what is the perimeter of a square which has sides of four x + six