This is an algabraic problem, so we would use variables:
Length=x
Width=y
The length is four times the width, so
x=4y
Since the equation for perimeter is P= 2(x+y), you would instead substitute 4y for x, and 7 for the perimeter.
7=2(4y+y)
Simplify.
7=2(5y)
7=10y
y=7/10
Since y is 7/10, you would substitute 7/10 into the equation x=4y.
x=4(7/10)
x=14/5
So, the dimensions are 7/10 x 14/5.
Hope this helps!
Answer:
47.1 inches
Step-by-step explanation:
The formula for finding circumference is C = D x pi
So, we go 15 x 3.14, and we get 47.1 inches
What the qoutient sweetheart
Answer:
2.5 cups is equal to 1 pound.
Step-by-step explanation:
___2.5__ cups rice is equivalent to 1 pound
Hope This Helped
Answer: r = C/(2pi)
This is the same as writing 
=========================================================
Explanation:
pi is some number (approximately 3.14) which means 2pi is also some number (roughly 6.28)
Saying c = 2pi*r means we have 2pi times r, and the result is the circumference c. To isolate r, we'll undo the multiplication. We'll undo it by dividing both sides by 2pi like so
C = 2pi*r
C/(2pi) = r
r = C/(2pi)
in which we can write it like 
So whatever C is, we divide it over 2pi (aka roughly 6.28) to get the radius.
-----------------
Extra Info (Optional Section):
As an example, let's say the circumference of the circle is 628 feet. This means the distance around the circle is 628 feet. So C = 628 would lead to...
r = C/(2pi)
r = C/(6.28)
r = 628/(6.28)
r = 100
So the radius would be roughly 100 feet.