Answer: 32.5 units (choice C)
This value is approximate.
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Step-by-step explanation:
To find the perimeter, we simply add up the lengths of the three external sides.
The horizontal side from D to E is 16 units long since |-10-6| = 16. I subtracted the x coordinates of the points and applied absolute value. You could also count out the spaces and you should count 16 spaces from D to E.
Unfortunately, the diagonal lengths aren't as straight forward. We have two options here: The pythagorean theorem, or the distance formula.
I'll go with the distance formula.
Let's find the distance from C to D, aka the length of side CD
Side CD is roughly 9.2195 units long.
Repeat this idea to find the length of CE
Side CE is roughly 7.2801 units long
The perimeter of triangle CDE is approximately...
P = DE+CD+CE
P = 16 + 9.2195 + 7.2801
P = 32.4996
This then rounds to 32.5 units. The answer is choice C.