Question

The length of a rectangle is 7 more than the width. The area is 744 square centimeters. Find the length and width of the rectangle.

Answer 1

Answer:

the width of the rectangle is 24 centimeters and the length is 31 centimeters.

Step-by-step explanation:

We first have to write an equation for this, but let's just recall that the area of a rectangle is equal to the length times the width. A=L×W.

A is the area

L is the length

W is the width.

So, for our equation we can start out by putting that 744= ? times ?.

So, we are given that the length is 7 more than the width. We are going to have to translate that to represent the length.

We need a variable. Let's use the letter "W," the width of the rectangle.

W=W.

The length is 7 more than the width, so it is L=W+7.

Length represents the W+7

Width represents W.

Now, we can complete our equation.

744=W(W+7).

Simplify the expression.

744=$W^{2}$+7W.

Alright, you may be thinking on how we are going to solve this problem. This equation correlates with quadratic functions.

Let's complete the square.

In a quadratic function, the standard from is y=$ax^{2} +bx+c$.

We need to find the c value.

We can do this by applying a formula. The formula states that c= b/2 and the whole thing squared. In other words, $(\frac{b}{2} )^{2}$.

In this case, the b value is 7.

square 7, which is 49 and square 2 which is 4.

Now, the c value is 49/4.

We have now just created a perfect square trinomial.

Not only do we add 49/4 to W squared plus 7W, we also add 49/4 to 744.

744 plus 49/4 is 756/25.

Now, we have $W^{2}+7w+\frac{49}{4} = 756.25$

Change W squared plus 7w plus 49/4 to a binomial squared.

Just take the square root of the a value, W, and 49/4 for c. the square root of W squared is W. the square root of 49/4 is 7/2.

Those values are to the power of 2.

In other words, $(W+\frac{7}{2})^{2} =756.25$

To isolate for W, take the square root of both sides.The square root of W plus 7/2 squared is just W+7/2. The square root of 756.25 is 27.5

There are two solutions for W because square roots be positive or negative, but we are dealing with positive since negative doesn't make sense with the context of the problem.

We have $W+3.5 or \frac{7}{2}=27.5$

Isolate for W by subtracting both sides by 3.5 You get to W=24.

Therefore, the width of the rectangle is 24 centimeters.

Alright, we found the width. We now need to find the length. The problem stated that the rectangle was 7 more than the width. So, 24+7=31. Therefore, the length of the rectangle is 31 centimeters.

L=31cm

W=24cm.

I hope this was helpful! I wish you have an amazing day!