3 years ago

What is the radius of a sphere which area is equal to the sum of the areas of four circles of radius 7?

Mathematics

1 answer:

antiseptic1488 [7]3 years ago

3 0

Answer:

radius = 7 units

Step-by-step explanation:

Given:

Radius = 7 units

Find area of 4 circles:

1 circle = π (7)² = 49π units²

4 circles = 49π x 4 = 196π units²

Find radius of sphere:

4πr² = 196π

r² = 49

r = 7

You might be interested in

Define f(0,0) in a way that extends f to be continuous at the origin. f(x, y) = ln ( 19x^2 - x^2y^2 + 19 y^2/ x^2 + y^2) Let f (

kirill115 [55]

Answer:

f(0,0)=ln19

Step-by-step explanation:

$f(x,y)=ln(\frac{19x^2-x^2y^2+19y^2}{x^2+y^2})$ is given as continuous function, so there exist $lim_{(x,y)\rightarrow(0,0)}f(x,y)$ and it is equal to f(0,0).

Put x=rcosA annd y=rsinA

$f(r,A)=ln(\frac{19r^2cos^2A-r^2cos^2A*r^2sin^2A+19r^2sin^2A}{r^cos^2A+r^2sin^2A})=ln(\frac{19r^2(cos^2A+sin^2A)-r^4cos^2Asin^a}{r^2(cos^2A+sin^2A)})$

we know that $cos^2A+sin^2A=1$ , so we have that

$f(r,A))=ln(\frac{19r^2-r^4cos^2Asin^a}{r^2})=ln(19-r^2cos^2Asin^2A)$

$lim_{(x,y)\rightarrow(0,0)}f(x,y)=lim_{r\rightarrow0}f(r,A)=ln19$

So f(0,0)=ln19.

8 0

3 years ago

What value is added to both sides of the equation x2 − 6x = 10 in order to solve by completing the square?

oksano4ka [1.4K]

To find the perfect square needed, you take the "middle" value and half it, then square it. so in this case, take -6, half it into 3, and square it to get 9. you'll be adding 9 to both sides

6 0

3 years ago

Given the number 2,357,841, in what place value is the 5?

mylen [45]

It is in the ten thousands place

8 0

3 years ago

Read 2 more answers

According to the survey described here, what was the sample of the survey? “A recent telephone survey of 900 teenagers aged 16 t

Ksivusya [100]

Answer:

i think its b