Calculate Rectangle Diagonal: Finding AC Length in 3×4 Rectangle

Question

Look at the rectangle ABC is below.

AB = 4

AD = 3

Determine the length of the diagonal AC?

00:00 Calculate AC

00:03 Opposite sides are equal in a rectangle

00:07 Side values according to the given data

00:11 Opposite sides are equal in a rectangle

00:15 Side values according to the given data

00:21 We'll use the Pythagorean theorem in triangle ABC

00:32 We'll substitute appropriate values and solve for AC

00:41 And this is the solution to the problem

In a rectangle, each pair of opposite sides are equal to each other, therefore:

$AB=DC=4$

We will use the Pythagorean theorem to find AC:

$AC^2=BC^2+DC^2$

Let's substitute the known data:

$AC^2=3^2+4^2$

$AC^2=9+16$

$AC^2=25$

Let's take the square root:

$AC=\sqrt{25}=5$

$5$