Answer: There are 10 sides
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x = measure of each interior angle
y = measure of each exterior angle
We know that x = 4y as "each interior angle is four times the measure of each exterior angle"
The interior and exterior adjacent angles are supplementary
x+y = 180
4y+y = 180
5y = 180
5y/5 = 180/5
y = 36
If y = 36, then
n = 360/y
n = 360/36
n = 10
Answer: 5.6 N/cm^2
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Work Shown:
Pressure = (Force)/(Area)
P = F/A
P = (84 N)/(15 cm^2)
P = (84/15) (N/cm^2)
P = 5.6 N/cm^2
For every square cm, 5.6 newtons of force is applied.
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Extra info:
If you wanted to convert this to pascals, then you would need to convert 15 cm^2 to 0.0015 square meters. Then apply the formula above to get 56,000 pascals. 1 pascal is equivalent to 1 N/m^2.