Question

What is the perimeter of triangle DEF?
Round your answer to the nearest tenth.

A.
12.2 units

B.
2.4 units

C.
4.2 units

D.
10.2 units

http://lv.k12.com/mediaFiles/Ninth_Grade/Math/Unit17844/Lesson69372/VHS_PA_S2_04_L207_L307_LQ_Q4.gif


i picked A @undeadknight26

Answer 1

Have you learned the Pythagorean Theorem?

Answer 2

Barely know it

Answer 3

Ok, here's a brief explanation.

Answer 4

Here's a right triangle.
The length of the legs (the sides that form the right angle) are a and b.
The length of the hypotenuse (the side opposite the right angle, and also the longest of the three sides) is c.

Answer 5

The Pythagorean theorem states that

\(a^2 + b^2 = c^2\)

The sum of the squares of the lengths of the legs equals the square of the length of the hypotenuse.

Answer 6

Here's an example with numbers that may be easier for you to understand. Then you can use this method in your own problem.

Answer 7

We have a right triangle in which the legs have lengths 3 and 4. We want to know the length of the hypotenuse, c.

Answer 8

All you do is follow the formula above.
Since we know the lengths of the legs, we substitute those values into a and b.
We can make a = 3, and b = 4. Then we solve for c.

\(a^2 + b^2 = c^2\)

\(3^2 + 4^2 = c^2\)

\(9 + 16 = c^2\)

\(25 = c^2\)

\(c^2 = 25\)

\(\sqrt{c^2} = \sqrt{25} \)

\(c = 5\)

In this case the hypotenuse has a length of 5.

Answer 9

Dont you divid the 5 by 2?

Answer 10

Wait nvm :o

Answer 11

Now we can use this same idea with your triangle.
To find the perimeter we need the lengths of all three sides.
From the graph, can you tell the lengths of the legs?

Answer 12

is f -2?

Answer 13

F is (-1, 4) and D is (-1, 1).
What is the distance DF?

Answer 14

I add them right

Answer 15

Since the x-coordinates are the same, you subtract 4 - 1.

Answer 16

3