Friday
March 24, 2017

Post a New Question

Posted by on Sunday, October 23, 2011 at 9:27am.

The length and width of a rectangle are (x+4) cm and x cm respectively. Write down expressions for:

A. The perimeter of the rectangle
B. The length of the side of a square with the same perimeter

If the sum of the areas of the square and the rectangle is 94 cm^2 , find x. Explain your working and solution

  • Math - , Sunday, October 23, 2011 at 9:40am

    a) P = 2(x+4) + 2x = 4x + 8

    b) if this had been a square, then each side would have been (4x+8)/4 = x+2

    x(x+4) + (x+2)^2 = 94
    x^2 + 4x + x^2 + 4x + 4 = 94
    2x^2 + 8x - 90 = 0
    x^2 + 4x - 45 = 0
    (x+9)(x-5) = 0
    x = a negative or x = 5

    check:
    rectange was 5 by 9 for an area of 45
    square was 7 by 7 for an area of 49
    total area is 45+49 = 94 ,
    all is good!

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question