Help please, don’t understand

Step-by-step explanation:

look at the drawing as two HALF circles and substract the larger half circle from the smaller half circle or the difference between two circles divided by two

A = π r² for a WHOLE circle     A / 2 is the area for a HALF circle

Area of the rainbow is     Large Circle Area / 2  - Small Circle Area / 2

=  (π r²/2 large - π r²/2 small)

=  (π r² large - π r² small) / 2

=  π( r² large -  r² small) / 2

= π ((18cm)² - (12cm)²) / 2

= π(324 -144)cm² / 2

= 282.74   <  FINAL ANSWER

answer: .64

step-by-step explanation

set up the formula for standard deviation for this set of numbers, then simplify