There are two (equivalent) formulas for the circumference of a circle:
C = 2 pi r, where r is the radius of the circle
C = pi d, where d is the diameter of the circle
In this particular problem, however, we're dealing with arc length. For the shown central angle "theta" = 160 degrees, the arc length is 42 cm.
Knowing this enables us to calculate the radius or diameter of the circle.
Arc length = s = (radius) (central angle, in radians, not degrees)
First, convert 160 degrees to radians: 160 deg pi rad
----------- * ------------ = (8/9) pi rad
1 180 deg
Then 42 cm = r *(8/9) pi rad
Solve for the radius (r): divide 42 cm by (8/9) pi rad
Then use the formula for circumference introduced earlier:
C= 2 pi r Substitute [42 cm / ( (8/9) pi rad )] for r.
Simplify your result, and you will then have the circumference, C, in cm.
Answer:
5x-y=-17
Step-by-step explanation:
that is the answer
Answer:
x-3=6
Step-by-step explanation:
Using the formula for area of a circle:
Area = pi x radius^2
Replace area with the given value:
39.62 = pi x radius^2
Divide both sides by pi
Radius^2 = 39.62/pi
Radius^2 = 12.62
Solve for radius by taking the square root of both sides
Radius = sqrt(12.62)
Radius = 3.55 cm
an = a1r^(n-1)
a5 = a1 r^(5-1)
-6 =a1 r^4
a2 = a1 r^(2-1)
-48 = a1 r
divide
-6 =a1 r^4
---------------- yields 1/8 = r^3 take the cube root or each side
-48 = a1 r 1/2 = r
an = a1r^(n-1)
an = a1 (1/2)^ (n-1)
-48 = a1 (1/2) ^1
divide by 1/2
-96 = a1
an = -96 (1/2)^ (n-1)
the sum
Sn = a1[(r^n - 1/(r - 1)]
S18 = -96 [( (1/2) ^17 -1/ (1/2 -1)]
=-96 [ (1/2) ^ 17 -1 /-1/2]
= 192 * [-131071/131072]
approximately -192
