All categories

3 years ago

4. What is the circumference of a circle whose area is 81π cm squared?

2 answers:

7 0

Area = pi*r^2
Circumference = 2pi*r

Step 1: find the radius from area
81pi=pi*r^2
81=r^2
9=r

Step 2: plug in radius to the circumference equation

Circumference = 2pi*r

18pi is the answer, otherwise know as 56.52 as well.

pogonyaev3 years ago

3 0

Step-by-step explanation:

Let us assume R be the radius of circle We know that, area of circle = πR2 81πr2 = πR2 R = √81 r R = 9r Circumference = 2 πr = 2 π (9r) = 18πr

You might be interested in

Find the slope of the roof of a home that rises 8 feet for every horizontal change of 24 feet

Mrrafil [7]

Rise over run 8\24 = 1/3

6 0

3 years ago

Solve x^2+ 4x =15<br> thxssss

dmitriy555 [2]

Answer:

x=3/5

Step-by-step explanation:

x^2+4x=5

x+4x=5x

5x+2=5

-2 -2

5x=3

divide 5 from each side

5/5x=3/5

7 0

3 years ago

PLEASE HURRY!

crimeas [40]

Answer:

Step-by-step explanation:

+7 means go up

if the graph was 7x, the graph enlarges by a factor of 7

6 0

3 years ago

Read 2 more answers

Lydia was out at a restaurant for dinner when the bill came. Her dinner came to $30. After adding in a tip, before tax, she paid

Aloiza [94]

Answer:

15%

Step-by-step explanation:

34.50-30=4.50

10% of 30= 3

5%of 30 = 1.50

3+1.50=4.50

so 4.50 = 15%

7 0

3 years ago

Read 2 more answers

If a number added to five is divided by the difference of the number and two, the result is three-fourths. Find the number.

alexandr1967 [171]

Answer:

x = - 26

Step-by-step explanation:

Let the number be x.

According to the question,

$\frac{x+5}{x-2} = \frac{3}{4}\\$

Cross multiplying 4 & 3 gives :-

$4(x+5)=3(x-2)$

And solving this eqn. gives :-

$4(x+5)=3(x-2)\\=> 4x+20=3x-6\\=>4x-3x=-20-6\\=>x=-26$

Verification :-

(putting the value of x = -26 )

$\frac{x+5}{x-2} \\\\=>\frac{-26+5}{-26-2} \\\\=> \frac{-21}{-28} \\\\=>\frac{21}{28}$

Reducing $\frac{21}{28}$ by 7 gives $\frac{3}{4}$ .

5 0

3 years ago