Find the dimensions of a rectangle
by a visitor
Question
The area of a rectangle is 45 square cm. If the length is 4 cm greater than the width, what is the dimensions of the rectangle?
Answer
The picture below shows the rectangle with the area of 45cm
2. Now, let the width be
w. Since, the length is 4cm greater than the width, the length will be
w+4 cm.
Before we can find the dimensions of the rectangle, we need find
w first. Here's how:
1) Write an equation that relates 45cm2, w+4 and w.To do so, we know that the area of the rectangle, 45cm
2 can be found by multiplying
w with
w+4. Hence, we have:
To continue, we need to remove the bracket and simplify the equation. This is shown below:
2) Solve the Quadratic EquationNotice that, now we have a quadratic equation:
To find
w, we need to solve the quadratic equation. One way to do so is to
factorize the quadratic equation. Hence, we have:
Now, since
w is the width of a rectangle. There is no way it can be a negative number. Therefore,
w must be 5.
With
w = 5. The...
...and the...
Below is the rectangle with its dimensions: