C = pi * d
a = pi * (d/2)^2
Answer: the speed of the current is 9 mph.
Step-by-step explanation:
Let x represent the speed of the current.
A boat can travel 21 mph in still water. If it travels 270 miles with the current. It means that the total speed with which the boat travelled with the current is (21 + x) mph.
Time = distance/speed
Time spent by the boat in travelling 270 miles is
270/(21 + x)
In the same length of time, it travels 108 miles against the current. It means that the total speed with which the boat travelled against the current is (21 - x) mph.
Time = distance/speed
Time spent by the boat in travelling 108 miles is
108/(21 - x)
Since the time is the same, then
270/(21 + x) = 108/(21 - x)
270(21 - x) = 108(21 + x)
5670 - 270x = 2268 - 108x
108x + 270x = 5670 - 2268
378x = 3402
x = 3402/378
x = 9
The mean score is 3.08.
There is 1 quiz with score 1, so 1 point; 3 quizzes with score 2 for 3*2 = 6 points; 4 quizzes with score 3 for 4*3 = 12 points; 4 quizzes with score 4 for 4*4 = 16 points; and 1 quiz with score 5 for 5 points.
This is a total of 1+6+12+16+5 = 40 points.
This is out of 1+3+4+4+1 = 13 quizzes.
40/13 = 3.08
Answer:
Perimeter is 17.07
Step-by-step explanation:
We know that DF = EF = 5 cm, since D and E are the midpoints of AC and AB, both of which are 10 cm in length.
We need to use the Pythagorean theorem to get the length of DE.
So the perimeter of DEF is 5 + 5 + 7.07 = 17.07
