Parallelogram Area Calculation: Using Height CE and Segments 5, 7, and 2

Question

ABCD is a parallelogram.

CE is its height.

CB = 5
AE = 7
EB = 2

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What is the area of the parallelogram?

Video Solution

Solution Steps

00:00 Find the area of the parallelogram
00:03 We'll use the Pythagorean theorem in triangle EBC
00:10 We'll substitute appropriate values and solve for EC
00:17 We'll isolate EC
00:27 This is the length of EC, which is the height of the parallelogram
00:33 To find the area, multiply the height(EC) by the side(AB)
00:40 The entire side equals the sum of its parts
00:55 We'll substitute appropriate values in the area formula and solve
01:03 And this is the solution to the problem

Step-by-Step Solution

To find the area,

first, the height of the parallelogram must be found.

To conclude, let's take a look at triangle EBC.

Since we know it is a right triangle (since it is the height of the parallelogram)

the Pythagorean theorem can be used:

a2+b2=c2 a^2+b^2=c^2

In this case: EB2+EC2=BC2 EB^2+EC^2=BC^2

We place the given information: 22+EC2=52 2^2+EC^2=5^2

We isolate the variable:EC2=52+22 EC^2=5^2+2^2

We solve:EC2=254=21 EC^2=25-4=21

EC=21 EC=\sqrt{21}

Now all that remains is to calculate the area.

It is important to remember that for this, the length of each side must be used.
That is, AE+EB=2+7=9

21×9=41.24 \sqrt{21}\times9=41.24

Answer

41.24