Hello!
To find the perimeter of the triangle, we need to find the length of all the sides using the <u>distance formula</u>.
The distance formula is:
.
First, we can find the distance between the points (-3, -1) and (2, -1). The point (-3, -1) can be assigned to
, and (2, -1) is assigned to
. Then, substitute the values into the formula.
![d =\sqrt{(2 - (-3))^{2}+ (-1 - (-1))^{2}}](https://tex.z-dn.net/?f=%20d%20%3D%5Csqrt%7B%282%20-%20%28-3%29%29%5E%7B2%7D%2B%20%28-1%20-%20%28-1%29%29%5E%7B2%7D%7D%20)
![d =\sqrt{5^{2}+0^{2}}](https://tex.z-dn.net/?f=%20d%20%3D%5Csqrt%7B5%5E%7B2%7D%2B0%5E%7B2%7D%7D%20)
The distance between the points (-3, -1) and (2, -1) is 5 units.
Secondly, we need to find the distance between the points (2, 3) and (2, -1). Assign those points to
and
, then substitute it into the formula.
![d =\sqrt{(2 - 2)^{2}+ (-1 - 3)^{2}}](https://tex.z-dn.net/?f=%20d%20%3D%5Csqrt%7B%282%20-%202%29%5E%7B2%7D%2B%20%28-1%20-%203%29%5E%7B2%7D%7D%20)
![d =\sqrt{0^{2}+(-4)^{2}}](https://tex.z-dn.net/?f=%20d%20%3D%5Csqrt%7B0%5E%7B2%7D%2B%28-4%29%5E%7B2%7D%7D%20)
![d =\sqrt{16} = 4](https://tex.z-dn.net/?f=%20d%20%3D%5Csqrt%7B16%7D%20%3D%204%20%20)
The distance between the two points (2, 3) and (2, -1) is 4 units.
Finally, we use the distance formula again to find the distance between the points (-3, -1) and (2, 3). Remember the assign the ordered pairs to
and
and substitute!
![d =\sqrt{(2 -(-3))^{2}+ (3 - (-1))^{2}}](https://tex.z-dn.net/?f=%20d%20%3D%5Csqrt%7B%282%20-%28-3%29%29%5E%7B2%7D%2B%20%283%20-%20%28-1%29%29%5E%7B2%7D%7D%20)
![d =\sqrt{5^{2}+4^{2}}](https://tex.z-dn.net/?f=%20d%20%3D%5Csqrt%7B5%5E%7B2%7D%2B4%5E%7B2%7D%7D%20)
![d =\sqrt{25 + 16}](https://tex.z-dn.net/?f=%20d%20%3D%5Csqrt%7B25%20%2B%2016%7D%20)
This is equal to approximately 6.40 units.
The last step is to find the perimeter. To find the perimeter, add of the three sides of the triangle together.
P = 5 units + 4 units + 6.4 units
P = 15.4 units
Therefore, the perimeter of this triangle is choice A, 15.4.