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givi [52]
2 years ago
14

Pls help me with this

Mathematics
1 answer:
Kryger [21]2 years ago
8 0

Answer:

A = kr²

Step-by-step explanation:

Given A is directly proportional to r² then the equation relating them is

A = kr² ← k is the constant of variation

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The length of a rectangle is 2 ft longer than its width. if the perimeter of the rectangle is 32 ft , find its area.
mash [69]
The length of would be 9 and the width 7, resulting in an area of 63
3 0
3 years ago
The standard IQ test has a mean of 97 and a standard deviation of 17. We want to be
densk [106]

Let's call our estimate x. It will be the average of n IQ scores. Our average won't usually exactly equal the mean 97.  But if we repeated averages over different sets of tests, the mean of our estimate the average would be the same as the mean of a single test,

μ = 97

Variances add, so the standard deviations add in quadrature, like the Pythagorean Theorem in n dimensions.  This means the standard deviation of the average x is

σ = 17/√n

We want to be 95% certain

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By the 68-95-99.7 rule, 95% certain means within two standard deviations. That means we're 95% sure that

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√n = 2 (17/5)

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We better round up.

Answer: We need a sample size of 47 to be 95% certain of being within 5 points of the mean

6 0
3 years ago
Can someone help me I will mark BRAINLIESt for the rest of my questionS!
Nonamiya [84]

Answer:

Answers are below

Step-by-step explanation:

Minimum: 2.50(1.01)^10 = $2.76

Maximum : 2.50(1.01)^20 = $3.05

If these answers are correct, please make me Brainliest!

8 0
3 years ago
Read 2 more answers
Work out the area of this circle witha diameter of 14cm give your answer in terms like and state its unit
zmey [24]

Answer:

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Step-by-step explanation:

its just the radius (half the diameter) squared (times by itself) then times by pi π, simpified, πR2

5 0
2 years ago
Read 2 more answers
1. Brian has three time
Naya [18.7K]
1. Translate words into equation :
Brian= b
Natasha =n
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2. Solve : 4n=88 (divide by 4)
N=22 so natasha has 22 marbles and since b=3n, brian has 66 marbles
5 0
8 months ago
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