Ask question

Ask question

All categories

3 years ago

10

Please help me with this thanks :)

1 answer:

SpyIntel [72]3 years ago

4 0

Answer:

Correct answer: SA = 108 · π ft²

Step-by-step explanation:

Given:

Diameter of the sphere d = 12 ft

d = 2 · r where r is radius

r = d / 2 = 12 / 2 = 6 ft

r = 6 ft

SA = 3 · r² · π

SA = 3 · 6² · π = 3 · 36 · π = 108 · π

SA = 108 · π ft²

God is with you!!!

You might be interested in

4.Which is the best buy in the following cases. a) 4pens for Rs 56 or 6pens for Rs 90 give full step of answer

Greeley [361]

Answer:

4 pens

Step-by-step explanation:

better value

6 0

3 years ago

What is the equivalent measure of 78 centiliters in milliliters?

Maurinko [17]

170 milliliters is the answer

3 0

3 years ago

Read 2 more answers

Solve for x. y +X=b Help!

neonofarm [45]

9514 1404 393

Answer:

x = b - y

Step-by-step explanation:

To get x by itself, subtract y from both sides.

y + x = b . . . . . . . . . given

y - y + x = b - y . . . . subtract y

x = b - y . . . . . . . . . simplify

7 0

3 years ago

Sometimes integers are encoded by using four-digit binary expansions to represent each decimal digit. this produces the binary c

wolverine [178]

<span>You're wasting a whole lot of possible 'space' in that encoding solution, but the answer is 4n. </span>

4 0

4 years ago

Please help solve these proofs asap!!!

timama [110]

Answer:

Proofs contained within the explanation.

Step-by-step explanation:

These induction proofs will consist of a base case, assumption of the equation holding for a certain unknown natural number, and then proving it is true for the next natural number.

a)

Proof

Base case:

We want to shown the given equation is true for n=1:

The first term on left is 2 so when n=1 the sum of the left is 2.

Now what do we get for the right when n=1:

$\frac{1}{2}(1)(3(1)+1)$

$\frac{1}{2}(3+1)$

$\frac{1}{2}(4)$

$2$

So the equation holds for n=1 since this leads to the true equation 2=2:

We are going to assume the following equation holds for some integer k greater than or equal to 1:

$2+5+8+\cdots+(3k-1)=\frac{1}{2}k(3k+1)$

Given this assumption we want to show the following:

$2+5+8+\cdots+(3(k+1)-1)=\frac{1}{2}(k+1)(3(k+1)+1)$

Let's start with the left hand side:

$2+5+8+\cdots+(3(k+1)-1)$

$2+5+8+\cdots+(3k-1)+(3(k+1)-1)$

The first k terms we know have a sum of .5k(3k+1) by our assumption.

$\frac{1}{2}k(3k+1)+(3(k+1)-1)$

Distribute for the second term:

$\frac{1}{2}k(3k+1)+(3k+3-1)$

Combine terms in second term:

$\frac{1}{2}k(3k+1)+(3k+2)$

Factor out a half from both terms:

$\frac{1}{2}[k(3k+1)+2(3k+2]$

Distribute for both first and second term in the [ ].

$\frac{1}{2}[3k^2+k+6k+4]$

Combine like terms in the [ ].

$\frac{1}{2}[3k^2+7k+4$

The thing inside the [ ] is called a quadratic expression. It has a coefficient of 3 so we need to find two numbers that multiply to be ac (3*4) and add up to be b (7).

Those numbers would be 3 and 4 since

3(4)=12 and 3+4=7.

So we are going to factor by grouping now after substituting 7k for 3k+4k:

$\frac{1}{2}[3k^2+3k+4k+4]$

$\frac{1}{2}[3k(k+1)+4(k+1)]$

$\frac{1}{2}[(k+1)(3k+4)]$

$\frac{1}{2}(k+1)(3k+4)$

$\frac{1}{2}(k+1)(3(k+1)+1)$ .

Therefore for all integers n equal or greater than 1 the following equation holds:

$2+5+8+\cdots+(3n-1)=\frac{1}{2}n(3n+1)$

//

b)

Proof:

Base case: When n=1, the left hand side is 1.

The right hand at n=1 gives us:

$\frac{1}{4}(5^1-1)$

$\frac{1}{4}(5-1)$

$\frac{1}{4}(4)$

$1$

So both sides are 1 for n=1, therefore the equation holds for the base case, n=1.

We want to assume the following equation holds for some natural k:

$1+5+5^2+\cdots+5^{k-1}=\frac{1}{4}(5^k-1)$ .

We are going to use this assumption to show the following:

$1+5+5^2+\cdots+5^{(k+1)-1}=\frac{1}{4}(5^{k+1}-1)$

Let's start with the left side:

$1+5+5^2+\cdots+5^{(k+1)-1}$

$1+5+5^2+\cdots+5^{k-1}+5^{(k+1)-1}$

We know the sum of the first k terms is 1/4(5^k-1) given by our assumption:

$\frac{1}{4}(5^k-1)+5^{(k+1)-1}$

$\frac{1}{4}(5^k-1)+5^k$

Factor out the 1/4 from both of the two terms:

$\frac{1}{4}[(5^k-1)+4(5^k)]$

$\frac{1}{4}[5^k-1+4\cdot5^k]$

Combine the like terms inside the [ ]:

$\frac{1}{4}(5 \cdot 5^k-1)$

Apply law of exponents:

$\frac{1}{4}(5^{k+1}-1)$

Therefore the following equation holds for all natural n:

$1+5+5^2+\cdots+5^{n-1}=\frac{1}{4}(5^n-1)$ .

//

5 0

3 years ago