A rectangle has a width of 9 units and a length of 40 units. What is the length of a diagonal? 31 units
39 units
41 units
49 units

41 units

Step 1: Write sample equation

This type of problem can be solved using Pythagorean theorem. In case you are unfamiliar with this type of formula, it is helpful to write the sample equation as the first step. Let’s put this below.

a²+b²= c²

The a and b will stand for the legs, in this case the width and the length. The c will be the diagonal, also referred to as the hypotenuse.

Step 2: Substitute numbers

Now that we have the information on the equation format, let’s substitute the numbers accordingly.

a²+b²= c²
9²+40²= c²

Since we are solving for the hypotenuse, the third value will remain as c.

Step 3: Solve

For the final step, let’s solve for c.

*Rewrite equation*
9²+40²= c²
*Find the squared value of each number*
81+1,600= c²
*Add 81 and 1,600*
1,681= c²
*Cancel out the squared sign by finding the square root of 1,681 and c²*
41= c²

This is your answer! The diagonal is equal to 41. Hope this helps! Comment below for more questions.

The first answer is correct