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2 years ago

I need help finding both volume and surface area

Mathematics

1 answer:

Svetradugi [14.3K]2 years ago

6 0

Answer:

Volume

For the rectangle, h = 3cm, l = 8cm, w = 6cm
V = length x width x height
V = 8cm x 6cm x 3cm
V = 144cm^3

For the semi circle, we need to find the radius. The radius is width/2, so 6cm/2 = 3cm. r = 3cm, $\pi$ = 3.14
V = radius^2 x height x $\pi$
V = 3cm^2 x 3cm x 3.14
V = 84.8 cm^3/2 (because the cylinder needs to be divided to form a semi-circle)
V= 42.4cm^3 (there are two cylinders though so we will multiply this by 2 in the total volume)

Total volume:
V = 144cm^3 + 42.4cm^3(2)
V = 186.4cm^3

Surface Area

Rectangular prism:
A = 2[w(l) + h(l) + h(w)]
A = 2[6cm(8cm) + 3cm(8cm) + 3cm(6cm)]
A = 180cm^2
But there are two sides that are covered by the semi-circular prisms, so we will have to calculate those sides and remove them.
A = l x w
A = 6cm x 3cm
A = 18cm^2(2) (2 being the two faces)
A = 36cm^2

A = 180cm^2 - 36cm^2
A = 144cm^2 (the area of the rectangle)

Semi-circular prism:
A = 2 $\pi$ rh + 2 $\pi$ r^2
Earlier, we found out that the radius of the circle is 3cm, so we will plug that in.
A = 2(3.14)(3cm)(3cm) + 2(3.14)(3cm)^2
A = 113.09cm^2

Total surface area:
A = 144cm^2 + 133.09cm^2
A = 277.09cm^2

Therefore the total volume of the prism is 186.4cm^3 and the total surface area is 277.09cm^2.

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Just number 7 would be fine but if you could also number 8 would help a lot

BlackZzzverrR [31]

Answer:

7. r = -5

8. x = -1

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Equality Properties

Step-by-step explanation:

Step 1: Define

r + 2 - 8r = -3 - 8r

Step 2: Solve for r

Combine like terms: -7r + 2 = -3 - 8r
Add 8r to both sides: r + 2 = -3
Subtract 2 on both sides: r = -5

Step 3: Check

Plug in r into the original equation to verify it's a solution.

Substitute in r: -5 + 2 - 8(-5) = -3 - 8(-5)
Multiply: -5 + 2 + 40 = -3 + 40
Add: -3 + 40 = -3 + 40
Add: 37 = 37

Here we see that 37 does indeed equal 37.

∴ r = -5 is a solution of the equation.

Step 4: Define equation

-4x = x + 5

Step 5: Solve for x

Subtract x on both sides: -5x = 5
Divide -5 on both sides: x = -1

Step 6: Check

Plug in x into the original equation to verify it's a solution.

Substitute in x: -4(-1) = -1 + 5
Multiply: 4 = -1 + 5
Add: 4 = 4

Here we see that 4 does indeed equal 4.

∴ x = -1 is a solution of the equation.

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3 years ago

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32% of college students say they use credit cards because of the rewards program. You randomly select 10 college students and a

Tems11 [23]

Answer:

a) $P(X=2)=(10C2)(0.32)^2 (1-0.32)^{10-2}=0.211$

b) $P(X> 2)=1-P(X\leq 2)=1-[0.0211+0.0995+0.211]=0.668$

c) $P(2 \leq x \leq 5)=0.211+0.264+0.218+0.123=0.816$

Step-by-step explanation:

1) Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

2) Solution to the problem

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=10, p=0.32)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Part a

$P(X=2)=(10C2)(0.32)^2 (1-0.32)^{10-2}=0.211$

Part b

$P(X> 2)=1-P(X\leq 2)=1-[P(X=0)+P(X=1)+P(X=2)]$

$P(X=0)=(10C0)(0.32)^0 (1-0.32)^{10-0}=0.0211$

$P(X=1)=(10C1)(0.32)^1 (1-0.32)^{10-1}=0.0995$

$P(X=2)=(10C2)(0.32)^2 (1-0.32)^{10-2}=0.211$

$P(X> 2)=1-P(X\leq 2)=1-[0.0211+0.0995+0.211]=0.668$

Part c

$P(2 \leq x \leq 5)=P(X=2)+P(X=3)+P(X=4)+P(X=5)$

$P(X=2)=(10C2)(0.32)^2 (1-0.32)^{10-2}=0.211$

$P(X=3)=(10C3)(0.32)^3 (1-0.32)^{10-3}=0.264$

$P(X=4)=(10C4)(0.32)^4 (1-0.32)^{10-4}=0.218$

$P(X=5)=(10C5)(0.32)^5 (1-0.32)^{10-5}=0.123$

$P(2 \leq x \leq 5)=0.211+0.264+0.218+0.123=0.816$

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Solution

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We want to convert this into quarts so we can do this:

$35Pts\cdot\frac{1quart}{2Pts}=17.5\text{quarts}$

Then the answer rounded to the nearest hundredth is:

17.50 quarts

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1 year ago

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Answer:

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Step-by-step explanation:

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3 years ago

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X+5 divided by 3=15 what is the answer?

GREYUIT [131]

All you have to do is solve for x. See the following steps below.

Step 1. Subtract $\frac{5}{3}$ from both sides

$X= 15-\frac{5}{3}$

Step 2. Simplify $15- \frac{3}{5}$ to $\frac{40}{3}$

$X= \frac{40}{3}$

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3 years ago

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