Amusical instrument has a pitch of 220 hertz when the wavelength is 3 feet. when the wavelength is 4 feet, the pitch is 165 hertz. what is the type of variation between pitch and wavelength? what is the pitch when the wavelength is 5 feet? hertz

We know that
Inverse Variation is a relationship between two variables in which the product is a constant
so
let
x> a pitch of a musical instrument
y> the wavelength
x*y=k

find the value of k

for x=220 hertz   y=3 ft
x*y=k
220*3=k
k=660

for x=165 hertz   y=4 ft
x*y=k
165*4=660
k=660

the answer part a) is
the type of variation between pitch and wavelength is an inverse variation

part b) What is the pitch when the wavelength is 5 feet?
x=?
y=5 ft
k=660
x*y=k> solve for x
x=k/y> x=660/5> x=132 hertz

the answer Part b) is
132 hertz

Variance is calculated  by taking the differences between each number in the set and the mean, then  squaring the differences (to make them positive) and dividing the sum of the squares by the number of values in the set. standard deviation is the square of the variance. hope this .