the first part isn't 90, it's 180.
the whole circle is 360, half of 360 is 180
an acute angle is any angle less than 90 degrees.
let's recall the vertical line test, it's a function if when dropping a vertical line on the graph, it only touches it once on the way down.
Check the picture below.
Answer:
254/324 which is about 78.4%
Step-by-step explanation:
found area of entire square to be 18² or 324
found area of 4-quarter circles - which equals one circle with radius of 9
A = 81π which is about 70
subtracted 324 and 70 to get 254
ratio of shaded to unshaded is 254 : 324
The first answer is the correct one
Answer:

Step-by-step explanation:
