In January, the depth of a lake was 1,008 feet. In August, the depth of the lake was 806.4 feet. What is the percentage decrease of the depth of the lake from January to August?

20%

Step-by-step explanation:

First you have to take 1008 and subtract 806.4. Once you get that answer you put it into a division problem. So answer over the first number, being 1008. Then multiply that answer by 100. and that is your percentage.

isocolese triangle

we know that the line connect a and b is the hyptonuse

so first find the hypotonuse length using the distance formula, call the length c

since it is an isocolese triangle, the lengths of the legs are the same

using pythagorean theorem,

in this case, a=b since isocolese triangle so we get

or

we can find c so we can find the distances

we know that if we draw 2 circles, each has center at a and b, and find where they intersect, we can the 2 possible locations for c

if a has center at (xa,ya) and b has center at (xb,yb), then we can solve where

and

intersect to find where they intersect

i'm not going to put an example because i have to go to class. i hope this explanation is enough