Calculate Rectangle Area: Using Given Dimensions 8 and 17

Question

Look at the following rectangle:

BC = 8

BD = 17

Calculate the area of the rectangle ABCD.

00:00 Calculate the area of rectangle ABCD

00:03 Side lengths according to given data

00:07 Let's use the Pythagorean theorem in triangle BCD

00:11 We'll do this to find CD

00:20 Let's isolate CD

00:31 This is the length of side CD

00:34 Now let's use the formula for calculating rectangle area

00:37 Side (8) multiplied by side (15)

00:40 And this is the solution to the question

We will find side DC by using the Pythagorean theorem in triangle DBC:

$BC^2+CD^2=BD^2$

Let's substitute the known data:

$8^2+CD^2=17^2$

$CD^2=289-64=225$

Let's take the square root:

$CD=15$

Now we have the length and width of rectangle ABCD and we'll calculate the area:

$15\times8=120$

120