Two years ago the water in a local reservoir fell 8 3/4 feet then it rose 4 3/5 how much did it change

WORK:
8 3/4 = 8 15/20
4 3/5 = 4 12/20

8 15/20 - 4 12/20 = 4 3/20

ANSWER:
4 3/20

To find the change, we need to subtract.

8 3/4 - 4 3/5

We need a common denominator to find the answer.

3*5/4*5 = 15/20

8 15/20

3*4/5*4 = 12/20

4 12/20

Now we can properly subtract

8-4=4

15-12
= 
  20 

3/20 

Now we have our final 4 3/20

The change : 4 3/20

Intersecting secant-tangent theorem states that if a tangent segment and a secant segment are drawn to a circle from an exterior point, then the square of the measure of the tangent segment is equal to the product of the measures of the secant segment and its external secant segment.so to break it down: 1. pq acts as the tangent and ps as the secant with an intersection at p.sr = 21rp = 3x + 3pq = 4x + 4following to equation: tangent squared = the two segments multiplied by each otherso (4x + 4) ^ 2 = (3x + 3) • (21) simplifies to 16x^2 - 31x - 47 = 0 or (16x - 47)(x + 1) x = -1 or x = 47/162. pq acts as the tangent and ps as the secant with an intersection at p (again! )sr = 16rp = xpq = 15(15) ^ 2 = 16 • x225 = 16xx = 225/163. the interesting chords are proportional to each other so a ratio is possible to set up: ap dp 10 3 + x = = —— = pc pb 8 xcross multiple to get 10x = (3 + x)(8)x = 12