We have two points describing the diameter of a circumference, these are:

Recall that the equation for the standard form of a circle is:

Where (h,k) is the coordinate of the center of the circle, to find this coordinate, we find the midpoint of the diameter, that is, the midpoint between points A and B.
For this we use the following equation:

Now, we replace and solve:

The center of the circle is (-8,-7), so:

On the other hand, we must find the radius of the circle, remember that the radius of a circle goes from the center of the circumference to a point on its arc, for this we use the following equation:

In this case, we will solve the delta with the center coordinate and the B coordinate.

Therefore, the equation for the standard form of a circle is:

In conclusion, the equation is the following:
Answer:
The distance across the lake is 3.5 km
Step-by-step explanation:
Hypotenuse is divided in equal parts. Thus both sides are divided in the same proportion.
Answer:
see below
Step-by-step explanation:
9/10
To get as a fraction over 100, multiply the top and bottom by 10
9*10 90
------ = ------------
10*10 100
9/10 = 90/100
The decimal form for 9/10 is .9 and for 90/100 is .90