(12 + 31). Find the midpoint m of 21 (8 + 5i) and 22 Express your answer in rectangular form.

Please help. Thank you!

katrin2010 [14]

Answer:

3a. ⇒ 2700 cm³

3b. ⇒ 72,900 cm³

3c. ⇒ 27

Step-by-step explanation:

3a.

∵ The model in a shape of square pyramid

∴ Its volume = base area × height

∵ Base shaped square with side length 15 cm

∴ Area of base = 15 × 15 = 225 cm²

∵ The model height = 12 cm

∴ She needs = 225 × 12 = 2,700 cm³ of plaster

3b.

∵ Each dimension in the actual stage = 3 times the model

∴ The side of the square base = 15 × 3 = 45 cm

∴ The height = 12 × 3 = 36 cm

∴ The area of the base = 45 × 45 = 2,025 cm²

∴ She needs = 2025 × 36 = 72,900 cm³ of plaster

3c.

∵ Each length in the actual stage is 3 times the model

∴ The volume of the actual stage = (3)³ the volume of the model

∴ The volume of the actual stage = 27 the volume of the model

<em>To check your answer:</em>

Volume actual ÷ Volume model = 72,900 ÷ 2700 = 27

3 0

3 years ago

You have a wire that is 20 cm long. You wish to cut it into two pieces. One piece will be bent into the shape of a square. The o

Aleksandr [31]

Answer:

Therefore the circumference of the circle is $=\frac{20\pi}{4+\pi}$

Step-by-step explanation:

Let the side of the square be s

and the radius of the circle be r

The perimeter of the square is = 4s

The circumference of the circle is =2πr

Given that the length of the wire is 20 cm.

According to the problem,

4s + 2πr =20

⇒2s+πr =10

$\Rightarrow s=\frac{10-\pi r}{2}$

The area of the circle is = πr²

The area of the square is = s²

A represent the total area of the square and circle.

A=πr²+s²

Putting the value of s

$A=\pi r^2+ (\frac{10-\pi r}{2})^2$

$\Rightarrow A= \pi r^2+(\frac{10}{2})^2-2.\frac{10}{2}.\frac{\pi r}{2}+ (\frac{\pi r}{2})^2$

$\Rightarrow A=\pi r^2 +25-5 \pi r +\frac{\pi^2r^2}{4}$

$\Rightarrow A=\pi r^2\frac{4+\pi}{4} -5\pi r +25$

For maximum or minimum $\frac{dA}{dr}=0$

Differentiating with respect to r

$\frac{dA}{dr}= \frac{2\pi r(4+\pi)}{4} -5\pi$

Again differentiating with respect to r

$\frac{d^2A}{dr^2}=\frac{2\pi (4+\pi)}{4}$ > 0

For maximum or minimum

$\frac{dA}{dr}=0$

$\Rightarrow \frac{2\pi r(4+\pi)}{4} -5\pi=0$

$\Rightarrow r = \frac{10\pi }{\pi(4+\pi)}$

$\Rightarrow r=\frac{10}{4+\pi}$

$\frac{d^2A}{dr^2}|_{ r=\frac{10}{4+\pi}}=\frac{2\pi (4+\pi)}{4}>0$

Therefore at $r=\frac{10}{4+\pi}$ , A is minimum.

Therefore the circumference of the circle is

$=2 \pi \frac{10}{4+\pi}$

$=\frac{20\pi}{4+\pi}$

4 0

2 years ago

What is the distance between two points located at<br> (5,-5) and (-3,-5)?

jenyasd209 [6]

Answer:the distance is 8

( this isn’t college math if anything it’s the ending and or beginning of 6th)

Step-by-step explanation:

3 0

3 years ago

The sales tax in one state is 5%. Write a function rule for finding the total cost of an item with selling price x. Then find th

Svetradugi [14.3K]

Answer:

f(x) = .05x; $5.50

Step-by-step explanation:

f(x) = .05x

f(110) = .05(110) = $5.50

8 0

2 years ago

Find the location of the absolute maximum and absolute minimum of the function on the interval [ -4,0).

N76 [4]

Maximum is 0 and minimum is -4. Due to the brackets, that means that this is where the value terminates. The parentheses next to the zero means equal to

3 0

3 years ago

(12 + 31). Find the midpoint m of 21 (8 + 5i) and 22 Express your answer in rectangular form.​

(12 + 31). Find the midpoint m of 21 (8 + 5i) and 22 Express your answer in rectangular form.