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3 years ago

I need help with this

Mathematics

1 answer:

MaRussiya [10]3 years ago

8 0

Answer:

number one is 3 Step-by-step explanation:

number 2

the answer is 2

number 3

answer is 42

number 4 answer is 15

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Jack has two square based pyramids that are the same size.he stick the square faces togather to make a new 3-d shape.how many fa

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I think it's
8faces and 6edges?

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3 years ago

Please I would be grateful if someone answer this question

Alina [70]

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3 years ago

A geometric series has second term 375 and fifth term 81 . find the sum to infinity of series .

Eduardwww [97]

Answer: $\bold{S_{\infty}=\dfrac{3125}{2}=1562.5}$

Step-by-step explanation:

a₁, 375, a₃, a₄, 81

First, let's find the ratio (r). There are three multiple from 375 to 81.

$375r^3=81\\\\r^3=\dfrac{81}{375}\\\\\\r^3=\dfrac{27}{125}\qquad \leftarrow simplied\\\\\\\sqrt[3]{r^3} =\sqrt[3]{\dfrac{27}{125}}\\ \\\\r=\dfrac{3}{5}$

Next, let's find a₁

$a_1\bigg(\dfrac{3}{5}\bigg)=375\\\\\\a_1=375\bigg(\dfrac{5}{3}\bigg)\\\\\\a_1=125(5)\\\\\\a_1=625$

Lastly, Use the Infinite Geometric Sum Formula to find the sum:

$S_{\infty}=\dfrac{a_1}{1-r}\\\\\\.\quad =\dfrac{625}{1-\frac{3}{5}}\\\\\\.\quad =\dfrac{625}{\frac{2}{5}}\\\\\\.\quad = \dfrac{625(5)}{2}\\\\\\.\quad = \large\boxed{\dfrac{3125}{2}}$

7 0

3 years ago

A fence is to be built to enclose a rectangular area of 1800 square feet. The fence along three sides is to be made of material

drek231 [11]

Answer:

length = 60 foot, width = 30 foot

Step-by-step explanation:

Area of rectangular part, A = 1800 ft²

Cost of fencing three sides is $ 6 per foot and cost of one side fencing is $18 per foot.

Let the length of the rectangle is l and the width of the rectangle is W.

Area = Length x width

A = L x W

1800 = L x W ...... (1)

Total cost of fencing, C = 6 x ( L + W + L) + 18 x W

C = 6 (2L + W) + 18 W

C = 12 L + 24 W

Substitute the value of W from equation (1), $W=\frac{1800}{L}$ in equation (2)

$C=12L+24\times \frac{1800}{L}$

$C=12L+\frac{43200}{L}$

Differentiate both sides with respect to L:

$\frac{dC}{dL}=12-\frac{43200}{L^{2}}$

Put it equal to zero for maxima and minima

$12-\frac{43200}{L^{2}}=0$

L = 60 foot

and W = 30 foot

So, the costing is minimum for length = 60 foot and the width = 30 foot.

4 0

3 years ago

Solve the equation. 5x + 8 - 3x = -10 x = -1 x=1 x=9

aksik [14]

Answer:

solution,

 $5x + 8 - 3x = - 10 \\ or \: 5x - 3x + 8 = -10 \\ or \: 2x + 8 = -10 \\ or \: 2x = -10 - 8 \\ or \: 2x = -18\\ or \: x = \frac{-18}{2 } \\ x = -9$ 

hope this helps..

Good luck on your assignment

7 0

4 years ago

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