proportion given that y is proportional to x, find the missing values of y x25102050 y18
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PROPORTION
Given that y is proportional to x, find the missing values of y
x 2 5 10 20 50
y 18
PROPORTION
The current, I, in a particular wire is proportional to the voltage, V. If I = 8 amps when V = 5 volts then find
(a)The current when the voltage is 8 volts
(b) The voltage if the current is 10 amps.
PROPORTION
There can be other ways in which two variables are directly proportional to each other.
Consider the formula for the area of a circle……
2rA A is directly proportional to the SQUARE of the radius. The constant k = 3.14….
PROPORTION
Other relationships to consider….
2xy
xy
y varies directly with the square of x
y varies directly with the square root of x
EXAMPLE
It is known that a is proportional to the square of n. Complete the table…
n 2 5 8 20
a 8 200
EXAMPLE 2
If a stone is dropped from the top of a building, the time t, to reach the ground is proportional to the square root of the height h of the building. Given that a stone takes 4.5 secs to fall 100 feet, how long will it take to fall 50 feet?
COMMON MISTAKE ! Do not halve the time!!!!!
FIND THE CONSTANT OF PROPORTIONALITY FIRST
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