Write the equation of a circle with center (4,5) and a circumference = 16 pi

The required equation in standard form is

Step-by-step explanation:

The equation of a circle with center (h,k) an radius, r units is given by the formula;

The given circle has center (4,5) and the radius can be calculated from the given circumference, which is

We substitute these values into the formula to obtain;

We simplify to get;

Equation of the circle : (x - 4)² + (y - 5)² = 64

Step-by-step explanation:

Equation of the circle

(x - x₁)² + (y - y₁)² = r²

Where (x₁, y₁) be the coordinates of center and r is the radius of circle.

To find the radius

It is given that circumference of circle = 16π

Circumference 2πr = 16

r = 16π/2π= 8

To find the equation of the circle

Center = (4, 5)

(x - x₁)² + (y - y₁)² = r²

(x - 4)² + (y - 5)² = 8²

(x - 4)² + (y - 5)² = 64

18

step-by-step explanation:

draw the shape and you will see that f and k are actually at adjacent vertices (points of the hexagon that are neighboring).   so find the distance between (1,2) and (4,2).   that is easy since (1,2) and (4,2) is just a vertical distance to count, which is 3.   it is a regular polygon which means all sides are congruent.   you have 6 sides (hexa) so multiply 6 by 3 to receive 18.

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

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