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3 years ago

What is the area of a circle if the radius is 7? Pease enter your answer as a decimal.

Mathematics

2 answers:

Ivahew [28]3 years ago

8 0

Answer:

A =153.86

Step-by-step explanation:

The area of a circle is given by

A = pi r^2 where r is the radius

A = pi (7)^2

A = 49 pi

Letting pi be approximated by 3.14

A = 49 *3.14

A =153.86

leva [86]3 years ago

8 0

Area of circle formula: A = πr^2

A = π(7)^2

A = π(49)

A = 153.86

Best of Luck!

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Two equations are given below:

jeka94

Siince 2nd equation is already equal a, subsitute b-2 for a in the other equation

b-2-3b=28
-2-2b=28
add 2 to both sides
-2b=30
divide both sides by -2
b=-15
sub back
a=b-2
a=-15-2
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3rd choice

4 0

3 years ago

I don’t understand this and it’s due tomorrow. Pls help

olya-2409 [2.1K]

Answer: H

Step-by-step explanation:

So this is called a problem you would use PEMDAS or (please-excuse-my-dear-aunt-sally)

Parenthesis

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In this sens, since parenthesis are present you do them first so it would be H

3 0

3 years ago

An explosion causes debris to rise vertically with an initial speed of 120 feet per second. The formula h equals negative 16 t s

Novay_Z [31]

Answer:

The debris will be at a height of 56 ft when time is <u>0.5 s and 7 s.</u>

Step-by-step explanation:

Given:

Initial speed of debris is, $s=120\ ft/s$

The height 'h' of the debris above the ground is given as:

$h(t)=-16t^2+120t$

As per question, $h(t)=56\ ft$ . Therefore,

$56=-16t^2+120t$

Rewriting the above equation into a standard quadratic equation and solving for 't', we get:

$-16t^2+120t-56=0\\\textrm{Dividing by -8 throughout, we get}\\\frac{-16}{-8}t^2+\frac{120}{-8}t-\frac{56}{-8}=0\\2t^2-15t+7=0$

Using quadratic formula to solve for 't', we get:

$t=\frac{-b\pm \sqrt{b^2-4ac}}{2a}\\\\t=\frac{-(-15)\pm \sqrt{(-15)^2-4(2)(7)}}{2(2)}\\\\t=\frac{15\pm \sqrt{225-56}}{4}\\\\t=\frac{15\pm\sqrt{169}}{4}\\\\t=\frac{15\pm 13}{4}\\\\t=\frac{15-13}{4}\ or\ t=\frac{15+13}{4}\\\\t=\frac{2}{4}\ or\ t=\frac{28}{4}\\\\t=0.5\ s\ or\ t=7\ s$

Therefore, the debris will reach a height of 56 ft twice.

When time $t=0.5\ s$ during the upward journey, the debris is at height of 56 ft.

Again after reaching maximum height, the debris falls back and at $t=7\ s$ , the height is 56 ft.

5 0

3 years ago

Complete the square to find the vertex of this parabola.PLEASE HELP!!

Paladinen [302]

Answer:

(1, 5 )

Step-by-step explanation:

Given

x² - 2x + y - 4 = 0 ( add 4 to both sides )

x² - 2x + y = 4

Complete the square on x² - 2x

add ( half the coefficient of the x term )² to both sides

x² + 2(- 1)x + 1 + y = 4 + 1, that is

(x - 1)² + y = 5

Subtract (x - 1)² from both sides

y = - (x - 1)² + 5

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

y = - (x - 1)² + 5 ← is in vertex form

with vertex = (1, 5 )

4 0

4 years ago

A recipe for sparkling grape juice calls for 1 1/2 quarts of sparkling water 3/4 quart of grape juice. Q1: How much sparkling wa

kogti [31]

Answer:

1) 18 Quart of Sparkling water need to mix with 9 quart grape juice

2) 15/2 Quart of grape juice required for 15/4 quarts of sparkling water.

3) Quantity of grape juice and sparkling water in 100 quart of punch are 33 1/3 quart and 66 2/3 quart respectively.

Step-by-step explanation:

1 1/2 quarts = 1 + (1/2) = 3/2 quarts

1) water required for 3/4 quart of grape juice = 3/2 quarts

so water required for 1 quart of grape juice = (3/2) ÷ (3/4) = (3/2)× (4/3) = 2 quarts

so water required for 9 quart of grape juice = 9 * 2 = 18 quart

18 Quart of Sparkling water need to mix with 9 quart grape juice

2) From solution of 1 ,

For 18 quart of Sparkling water , grape juice require = 9 quart

So for 1 quart of Sparkling water , grape juice require = 9÷18 = 1/2 Quart

so for 15/4 quart of Sparkling water , grape juice require = 1/2 × 15/4 =

15/2 Quart of grape juice required for 15/4 quarts of sparkling water.

in 1 we calculated that 18 Quart of Sparkling water need to mix with 9 quart grape juice that is 2 quart of Sparkling water need to mix with 1 quart of grape juice.

In other words 1 quart of grape juice + 2 quart of sparkling water is 3 quart of punch.

Quantity of Grape juice in 3 quart of punch = 1 quart

so quantity of grape juice in 1 quart of punch = 1/3 quart

And quantity of grape juice in 100 quart of punch = 100×(1/3) = 100/3 =

33 1/3

Quantity of sparkling water in 3 quart of punch = 2 quart

so quantity of sparkling water in 1 quart of punch = 2/3 quart

And quantity of sparkling water in 100 quart of punch = 100 ×2/3 quart = 66 2/3

3 0

3 years ago