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3 years ago

PLS HELP ASAP DUE IN 40 MINUTES

Mathematics

2 answers:

Art [367]3 years ago

8 0

The pyramid has 2 pairs of congruent faces. the opposite faces will be congruent as their base length will be the same. this can be proven using SSS congruence. if the base is a square, only then can we say that all 4 faces are congruent.
Hope this helps :)

Dmitriy789 [7]3 years ago

3 0

Answer:

It is (A) 4 congruent faces

Step-by-step explanation:

Easy to see how its the Base sides

-Hope it helped

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Suppose Becky invests in an annuity that pays 4.3% annual interest, compounded monthly and contributes $225 every month for 20 y

aleksklad [387]

Answer:

$85365.90

Step-by-step explanation:

Let's start by finding the effective rate of interest

.043/12=.00385333

$225*\frac{(1+.00385333)^{20*12}-1}{.00385333}=85365.89513$

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3 years ago

If x = 4, what is the value of 2x2 - 7?

Fudgin [204]

Answer:

A) 25

Step-by-step explanation:

I am assuming that you mean: 2x² - 7.

$2(4)^2 - 7\\\rule{150}{0.5}\\\rightarrow 2 *4^2 - 7\\\\\rightarrow 2 * 16 - 7\\\\\rightarrow 32 -7\\\\\rightarrow \boxed{25}$

5 0

3 years ago

Read 2 more answers

At 2 PM, a thermometer reading 80°F is taken outside where the air temperature is 20°F. At 2:03 PM, the temperature reading yiel

Alexeev081 [22]

Use Law of Cooling:
$T(t) = (T_0 - T_A)e^{-kt} +T_A$
T0 = initial temperature, TA = ambient or final temperature

First solve for k using given info, T(3) = 42
$42 = (80-20)e^{-3k} +20 \\ \\ e^{-3k} = \frac{22}{60}=\frac{11}{30} \\ \\ k = -\frac{1}{3} ln (\frac{11}{30})$

Substituting k back into cooling equation gives:
$T(t) = 60(\frac{11}{30})^{t/3} + 20$

At some time "t", it is brought back inside at temperature "x".
We know that temperature goes back up to 71 at 2:10 so the time it is inside is 10-t, where t is time that it had been outside.
The new cooling equation for when its back inside is:
$T(t) = (x-80)(\frac{11}{30})^{t/3} + 80 \\ \\ 71 = (x-80)(\frac{11}{30})^{\frac{10-t}{3}} + 80$
Solve for x:
$x = -9(\frac{11}{30})^{\frac{t-10}{3}} + 80$
Sub back into original cooling equation, x = T(t)
$-9(\frac{11}{30})^{\frac{t-10}{3}} + 80 = 60 (\frac{11}{30})^{t/3} +20$
Solve for t:
$60 (\frac{11}{30})^{t/3} +9(\frac{11}{30})^{\frac{-10}{3}}(\frac{11}{30})^{t/3} = 60 \\ \\ (\frac{11}{30})^{t/3} = \frac{60}{60+9(\frac{11}{30})^{\frac{-10}{3}}} \\ \\ \\ t = 3(\frac{ln(\frac{60}{60+9(\frac{11}{30})^{\frac{-10}{3}}})}{ln (\frac{11}{30})}) \\ \\ \\ t = 4.959$

This means the exact time it was brought indoors was about 2.5 seconds before 2:05 PM

8 0

4 years ago

The average of 10 numbers is 85. If the numbers 70 and 76 are removed from the set of numbers, what is the average of the remain

Alexeev081 [22]

Answer:

Step-by-step explanation:

From the question:

The average of 10 numbers is 85.

We have to find the total sum for the 10 numbers

Hence: 10 × 85 = 850

If the numbers 70 and 76 are removed from the set of numbers.

This means 10 number is reduced by 2

= 10 - 2 = 8

The total sum of the 8 numbers is

= 850 - (70 + 76)

= 850 - 146

= 704

The average of the remaining numbers is calculated as:

Sum of the 8 numbers/8

= 704/8

= 88.

Therefore, the sum of the remaining numbers is 88

4 0

3 years ago

You are at the music store to buy some CDs. You have $45 to spend and the store sells CDs for $12.99 each.

stealth61 [152]

$45>(or equal to)$12.99n you can spend less then or equal to forty five dollars without going into debt.

8 0

3 years ago