You can
put this solution on YOUR website!The perimeter of a rectangle is 64cm. The length of the rectangle is 2cm more than 1 and 1/2 times the width. Find the dimensions of the rectangle.
Underneath this, the teacher has written:
Find and write the two equations.
Solve the system by graphing.
:
Since we will be graphing
Let x = the width
Let y = the length
:
The 1st equation is is easy, the perimeter equation:
2x + 2y = 64
Simplify, divide equation by 2
x + y = 32
Put it in the general (y=) form for graphing
y = 32 - x
Plot it for x = 0 and x = 4
x | y
-------
0 |32
4 |28
:
Get the 2nd equation from the statement:
"The length of the rectangle is 2cm more than 1 and 1/2 times the width."
y = 1.5x + 2
Plot this for x = 0 and x = 4
x | y
--------
0 | 2
4 | 8
:
your graph should look like this:
:
With a calibrated eyeball you can see they intersect at x=12, y=20 and this
is solution to the system
;
You can confirm our solution by substitution in both equations
2(12) + 2(20) = 64
and
20 = 1.5(12) + 2
:
Did you follow what went on here? Any questions?
