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3 years ago

How do you find the surface area of a sphere?

Mathematics

1 answer:

Mamont248 [21]3 years ago

8 0

A=4πr^2 or in other words 4(3.14)r^2 (^2 stands for squared)

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Daunted spent two thirds of his savings on a car. He spent one-fourth of his remaining savings on a phone that cost $250. What w

krek1111 [17]

Answer:

Maybe the answer is $3000

7 0

2 years ago

Read 2 more answers

Susan needs to buy 3 helium balloons. She can buy individual balloons for $2.75 each, or a 3-pack of balloons for $7.80. How muc

Mrac [35]

Answer:

Step-by-step explanation:

8.25 minus 7.80 is 0.45 45 divided by 3 is 15 so the answer is 15

8 0

3 years ago

You can buy a CD the sale price of $6. This is 25% off of the original price. What is the original price of the CD?

Naya [18.7K]

6*.75=4.5

Thank you hope this helps

3 0

2 years ago

Suppose the waiting times in an emergency room are normally distributed with a mean (mean) of 40 and a standard deviation (sigma

kipiarov [429]

Answer:

0.68269

Step-by-step explanation:

When we are to find the z score for population where a random sample is picked, the z.score formula we use is

z = (x-μ)/Standard error, where

x is the raw score,

μ is the population mean

Standard error = σ/√n

σ is the population standard deviation

n = random number of samples

For : x = 38 minutes, μ = 40, σ = 10, n = 5

z = 38 - 40/10 /√25

= -2/10/5

= -2/2

= -1

Determining the probability value using z table

P(x = 38) = P(z = -1)

= 0.15866

For : x = 42 minutes, μ = 40, σ = 10, n = 25

z = 42 - 40/10 /√25

= 2/10/5

= 2/2

= 1

Determining the probability value using z table

P(x = 42) = P(z = 1)

= 0.84134

The probability that their average waiting time will be between 38 and 42 minutes is calculated as

P(-Z<x<Z)

= P(-1 < x < 1)

= P(z = 1) - P(z = -1)

= 0.84134 - 0.15866

= 0.68269

Therefore, the probability that their average waiting time will be between 38 and 42 minutes is 0.68269

3 0

3 years ago

Two corresponding sides of similar triangles are 2 cm and 5 cm. What is the area of the second triangle if the area of the first

Stella [2.4K]

Answer:

(1) Area of second triangle= 50 cm^2.

(2) Area of ΔABC=98 cm^2.

and Area of ΔDFG=175 cm^2.

Step-by-step explanation:

<em>" For two similar triangles the ratio of sides is equal to the ratio of square of their areas".</em>

i.e. if a,b are the corresponding sides of two similar triangles and let A and B denote the area of two triangles then we have the relation as:

$\dfrac{a^2}{b^2}=\dfrac{A}{B}$

(1)

for the first question:

we have a=2, b=5.

A=8 cm^2.

Hence,

$\dfrac{2^2}{5^2}=\dfrac{8}{B}\\\\\dfrac{4}{25}=\dfrac{8}{B}$

B=50 cm^2.

Hence, the area of second triangle is 50 cm^2.

(2)

In second option we have:

a=6 and b=5.

A-B=77 cm^2.

A=77+B

$\dfrac{6^2}{5^2}=\dfrac{A}{B}\\ \\\dfrac{36}{25}=\dfrac{77+B}{B}\\ \\36B=25\times77+25B\\\\36B-25B=25\times77\\\\11B=25\times77\\\\B=25\times7\\\\B=175$

Hence area of second triangle i.e. ΔDFG is 175 cm^2.

and area of first triangle i.e. ΔABC=175-77=98 cm^2.

8 0

2 years ago