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3 years ago

A circle has an area of 78.5 square inches. What is the radius of the circle?

Mathematics

1 answer:

Rainbow [258]3 years ago

6 0

Answer:

$\sqrt{24.98732606$ Decimal Form:

4.99873244

Step-by-step explanation:

geometry is the worst. but i have a way to remember how to find the area. (Apple Pies are too --> A=πr^2 --> area = pie×radius^squared) so basically you sub in 78.5 in for area and then you solve for r.

Hope i helped kinda lol

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Find the length of the short leg of a 30-60-90 triangle if the long leg is 3cm

antoniya [11.8K]

Answer:

Short leg = √3 cm

Step-by-step explanation:

the opposite angle of long leg is 60°

hypotenuse : x

sin 60° = 3/x = √3 / 2

x = (3 x 2) / √3 = 2√3

short leg length (s)

Cos 60° = 1/2 = s / x = s / 2√3

s = √3

7 0

3 years ago

Let y′′′−9y′′+20y′=0. find all values of r such that y=erx satisfies the differential equation. if there is more than one correc

DerKrebs [107]

we are given

differential equation as

$y'''-9y''+20y'=0$

we are given

$y=e^{rx}$

Firstly, we will find y' , y'' and y'''

those are first , second and third derivative

First derivative is

$y'=re^{rx}$

Second derivative is

$y''=r*re^{rx}$

$y''=r^2e^{rx}$

Third derivative is

$y'''=r^2*re^{rx}$

$y'''=r^3e^{rx}$

now, we can plug these values into differential equation

and we get

$r^3 e^{rx}-9r^2 e^{rx}+20re^{rx}=0$

now, we can factor out common terms

$e^{rx}(r^3 -9r^2 +20r)=0$

we can move that term on right side

$(r^3 -9r^2 +20r)=0$

now, we can factor out

$r(r^2 -9r +20)=0$

$r(r-5)(r-4)=0$

now, we can set them equal

$r=0$

$r-5=0$

$r=5$

$r-4=0$

$r=4$

so, we will get

$r=0,4,5$ ...............Answer

4 0

3 years ago

Graph the equations to solve the system y=x+4 y= -x - 6

Mama L [17]

Answer:

(-5, -1)

General Formulas and Concepts:

<u>Algebra I</u>

Functions

Graphing

Reading a Cartesian Plane
Coordinates (x, y)

Solving systems of equations by graphing

Step-by-step explanation:

Where the 2 equations intersect is the solution to the systems of equations.

5 0

2 years ago

A car is traveling at a rate of 50 miles per hour, while a motorcycle is traveling at 70 miles per hour. The car takes 4 hours l

mihalych1998 [28]

Answer:

Step-by-step explanation:

the answers are

3 0

3 years ago

Tell whether the lines of the pair of equations are parallel, perpendicular, or neither.

tino4ka555 [31]

First Equation:

$y= -\frac{3}{4} x+2$

Second Equation can be written as:

$y= \frac{3}{4}x+2$

Slope of first equation is -3/4 and slope of second equation is 3/4.
Slope of parallel lines must be equal, and slope of perpendicular lines are the negative reciprocal of each other. None of these conditions can be seen for given two equations.

So, the two lines are neither parallel nor perpendicular.
So correct option is C

7 0

3 years ago

Read 2 more answers