A sailing course is in the shape of an equilateral triangle. If the course has an altitude of 9 mi, what is the perimeter of the triangle?

27mi

Step-by-step explanation:

Since the sailing course is equilateral in shape, then all their sides are equal.

Get one of the sides using Pythagoras theorem as shown;

Let one of the side be x

Two base will be x/2

According to the theorem;

x² = 9² +(x/2)²

x² = 81 + x²/4

x²-x²/4 = 81

3x²/4 = 81

3x² = 324

x² = 324/4

x² = 81

x = 9

Perimeter of the triangle = 3x

Perimeter of the triangle = 3(9)

Perimeter of the triangle = 27mi

to plot points   for x just start at the origin (middle) and go to the left however many times it say(if the number is a positive) if the number is a negative then go right however many times it says if it is 0 go nowhere

now keep you pencil there and go up however many times it says on y(if it is positive) if it is negative then go down however many times it says. if it says 0 go nowhere.

you have just plotted a point! now when you finish plotting all of them connect them with a ruler

plot each point as (-3, 7), (0,4), (3,1), (8,-4)   in the parenthesis on the left of the comma is x and the right is y.