72 is the answer you are looking for here
Answer:
Option A. 
Step-by-step explanation:
we know that
The combined area of the 3 windowpanes and frame is equal to

using a graphing tool to solve the quadratic equation
The solution is 
see the attached figure
Step-by-step explanation:
The plumber's daily earnings have a mean of $145 per day with a standard deviation of
$16.50.
We want to find the probability that the plumber earns between $135 and
$175 on a given day, if the daily earnings follow a normal distribution.
That is we want to find P(135 <X<175).
Let us convert to z-scores using

This means that:

We simplify to get:

From the standard n normal distribution table,
P(z<1.82)=0.9656
P(z<-0.61)=0.2709
To find the area between the two z-scores, we subtract to obtain:
P(-0.61<z<1.82)=0.9656-0.2709=0.6947
This means that:

The correct choice is C.
I believe it's A. Day 1 decreased by half from 8 would be 4. Day 2 decreased by half from 4 would be 2. Day 3 decreased by half from 2 would be 1. then .5 would be decrease by. 25, which would be .75. I hope that makes sense:)
72⁰_______3π m
360⁰______15π m
C = 15π = 2π r
r = 7•5 m