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Evaluating formulas
To figure out the area of a circle with a radius of 5 inches, simply substitute r = 5 into the formula
A = πr2
in which r is the radius of the circle.
The answer is A = 25π = 78.5 square inches
Example 1
To convert the temperature in degrees Fahrenheit into the temperature in degrees
Celsius, we can use the formula
in which C is the temperature in degrees Celsius, F is the temperature in degrees Fahrenheit.
Use the formula to figure out the temperature in degrees Celsius, if
1) the temperature is 5 degrees Fahrenheit.
2) the temperature is 32 degrees Fahrenheit.
3) the temperature is 50 degrees Fahrenheit.
Solution
1)
The temperature in degrees Celsius is
= -15
2)
The temperature in degrees Celsius is
= 0
3)
The temperature in degrees Celsius is
= 10