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3 years ago

I will give brainiest

Mathematics

1 answer:

forsale [732]3 years ago

7 0

Answer:

A is equal to <em>20.</em>

Step-by-step explanation:

To find the missing side we have to square both 21 and 29.

Because 21 x 21 = 441, and 29 x 29 = 841, all we have to do is subtract 841 from 441 and we have 400.

Now we have to find the square root of 400, since 20 x 20 = 400, that means 20 is our answer.

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What is the altitude of an equilateral triangle that has sides of length 40 cm?

Rus_ich [418]

Answer:

Step-by-step explanation:

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3 years ago

The half-life of a radioactive substance is the time it takes for a quantity of the substance to decay to half of the initial am

posledela

Step-by-step walkthrough:

Well a standard half-life equation looks like this.

$N = N_0 * (\frac{1}{2})^{t/p$

$N_0$ is the starting amount of parent element.

$N$ is the end amount of parent element

$t$ is the time elapsed

$p$ is a half-life decay period

We know that the starting amount is 74g, and the period for a half-life is 2.8 days.

Therefore you can create a function based off of the original equation, just sub in the values you already know.

$N(t) = 74g * (\frac{1}{2})^{t/2.8days$

This is easy now that we have already made the function. Here we just reuse it, but plug in 2.8 days.

$N(t) = 74g * (\frac{1}{2})^{t/2.8days} = N(2.8days) = 74g * (\frac{1}{2})^{2.8days/2.8days}\\= 74g * \frac{1}{2} = 37g$

Now we just gotta do some algebra. Use the original function but this time, replace $N(t)$ with 10g and solve algebraically.

$10g = 74g * (\frac{1}{2})^{t/2.8days}\\\\\frac{10g}{74g} = (\frac{1}{2})^{t/2.8days}$

Take the log of both sides.

$log(\frac{5}{37}) = log((\frac{1}{2})^{t/2.8days})$

Use the exponent rule for log laws that, $log(b^x) = x*log(b)$

$log(\frac{5}{37}) = \frac{t}{2.8days} * log(\frac{1}{2})$

$\frac{log(\frac{5}{37})}{log(\frac{1}{2})} = \frac{t}{2.8days}$

$2.8 * \frac{log(\frac{5}{37})}{log(\frac{1}{2})} = t$

slap that in your calculator and you get

$t = 8.1 days$

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2 years ago

What is the value of the underline digit 72

bogdanovich [222]

The value of the 7 is 70 and the value of the 2 is 2.

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4 years ago

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What is the reciprocal of 10/3

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Reciprocal is basically just swapping them around, so for 10/3 it's 3/10 and that's your answer!

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3 years ago

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Answer:

Step-by-step explanation:

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