Answer:
about 8 cm
Step-by-step explanation:
The formula for the area of a regular polygon is ...
A = 1/2Pa . . . . where P is the perimeter and "a" is the apothem, the distance from the center to a side
Filling in your numbers, we have ...
20 cm^2 = (1/2)P(5 cm)
Dividing by the coefficient of P, we find ...
2×(20 cm^2)/(5 cm) = P = 8 cm
The perimeter of the pentagon is about 8 cm.
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<em>Comment on the problem</em>
This calculation makes use of the area formula, as apparently intended. A regular pentagon with an apothem of about 5 cm will have an area of about 90.8 cm^2. The given geometry is impossible, as the pentagon is nearly 10 cm across. It cannot have a perimeter of only 8 cm.
Answer:
Speed of Jet in Still Air = 265 miles per hour
Speed of Wind = 22 miles per hour
Step-by-step explanation:
Let x be speed of jet
and c be speed of wind
We know D = RT, where
D is distance
R is rate
T is time
For first leg:
1435 miles in 5 hours, the rate is:
Rate = 287 mph
For second leg:
1215 miles in 5 hours, the rate is:
Rate = 243 mph
So 287 is with wind and 243 against wind, thus we can write:
x + c = 287
x - c = 243
Adding gives us:
2x = 530
x = 265 miles per hour [still rate]
Speed of wind:
x + c = 287
265 + c = 287
c = 22 miles per hour [speed of wind]
B. 12 and 25 is the answer.....
Hope this helps!
