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3 years ago

I need help with these please!!

Mathematics

2 answers:

emmainna [20.7K]3 years ago

7 0

Answer:

can you zoom it

Step-by-step explanation:

Aleonysh [2.5K]3 years ago

3 0

Use photomath it’s faster and you get correct Answers!<3 have a good day

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I keep getting this wrong, please help me

Marat540 [252]

Answer:

Step-by-step explanation:

Circumference = 2πr

Let's set the equation equal to the formula:

16 = 2πr

16/2 = πr

8 = πr

r = 8/π

8 0

2 years ago

A plane flying horizontally at an altitude of "1" mi and a speed of "430" mi/h passes directly over a radar station. Find the ra

Anika [276]

Answer:

The rate at which the distance from the plane to the station is increasing when it is 2 mi away from the station is 372 mi/h.

Step-by-step explanation:

Given information:

A plane flying horizontally at an altitude of "1" mi and a speed of "430" mi/h passes directly over a radar station.

$z=1$

$\frac{dx}{dt}=430$

We need to find the rate at which the distance from the plane to the station is increasing when it is 2 mi away from the station.

$y=2$

According to Pythagoras

$hypotenuse^2=base^2+perpendicular^2$

$y^2=x^2+1^2$

$y^2=x^2+1$ .... (1)

Put z=1 and y=2, to find the value of x.

$2^2=x^2+1^2$

$4=x^2+1$

$4-1=x^2$

$3=x^2$

Taking square root both sides.

$\sqrt{3}=x$

Differentiate equation (1) with respect to t.

$2y\frac{dy}{dt}=2x\frac{dx}{dt}+0$

Divide both sides by 2.

$y\frac{dy}{dt}=x\frac{dx}{dt}$

Put $x=\sqrt{3}$ , y=2, $\frac{dx}{dt}=430$ in the above equation.

$2\frac{dy}{dt}=\sqrt{3}(430)$

Divide both sides by 2.

$\frac{dy}{dt}=\frac{\sqrt{3}(430)}{2}$

$\frac{dy}{dt}=372.390923627$

$\frac{dy}{dt}\approx 372$

Therefore the rate at which the distance from the plane to the station is increasing when it is 2 mi away from the station is 372 mi/h.

6 0

3 years ago

Zina goes shopping. She buys in the same store two scarves and three T-shirts for

Umnica [9.8K]

Answer:

The price of T-shirts before the sale = 42 euros

The price of scarves before the sale = -77/2 euros

Step-by-step explanation:

The cost of the items Zina buys from the store initially are;

Two scarves and three T-shirts for 49 euros

The reduction in the price of scarves a week later during sales = 1.5 euros

The reduction in the price of T-shirts a week later during sales = 2 euros

The items Zina bought for 40 euros at the reduced price of the sales opportunity are;

Four scarves and five T-shirts for 40 euros

Let 'x' represent the initial price of a scarf and let 'y' represent the initial price of a T-shirt, we have;

2·x + 3·y = 49...(1)

4·(x - 1.5) + 5·(y - 2) = 40...(2)

Expanding equation (2) gives;

4·x - 6 + 5·y - 10 = 40

4·x + 5·y = 40 + 6 + 10 = 56

∴ 4·x + 5·y = 56...(3)

By multiplying equation (1) by 2 and subtracting the result from equation (3), we get;

4·x + 5·y - 2 × (2·x + 3·y) = 56 - 2 × 49 = -63

-y = -42

y = 42

The price of T-shirts before the sale = 42 euros

x = (49 - 3 × 42)/2 = -77/2

x = -77/2

The price of scarves before the sale = -77/2 euros

(However, if the had bought the 4 scarves and 5 T-shirts during sales at 70 euros, we get;

The price of T-shirts before the sale = 12 euros

The price of scarves before the sale = 6.5 euros.

The allowable total price for the reduced 4 scarves and 5 T-shirts is between 66 and about 82 for both initial prices to be +ve)

6 0

3 years ago

18,000 amounts to 21,600 in 4 years at simple interest. Find the sum of

AnnyKZ [126]

Answer:

$\$20,400$

Step-by-step explanation:

we know that

The simple interest formula is equal to

$A=P(1+rt)$

where

A is the Final Investment Value

P is the Principal amount of money to be invested

r is the rate of interest

t is Number of Time Periods

step 1

Find the rate of interest

in this problem we have

$t=4\ years\\ P=\$18,000\\ A=\$21,600\\r=?$

substitute in the formula above and solve for r

$\$21,600=\$18,000(1+4r)$

$1.2=(1+4r)$

$4r=1.2-1$

$r=0.2/4=0.05$

The rate of interest is $5\%$

step 2

Find the sum of money that will amount to 25,500 in 5 years, at the same rate of interest

in this part we have

$t=5\ years\\ P=?\\ A=\$25,500\\r=0.05$

substitute in the formula above and solve for P

$\$25,500=P(1+0.05*5)$

$P=\$25,500/(1.25)=\$20,400$

3 0

3 years ago

I NEED HELP ASP 20 points

leva [86]

Circumference
C = pi d
C = 3.14 x 10
C = 31.4 cm

Area
A = pi r^2
A = 3.14 x 5^2
A = 78.5 cm^2

8 0

3 years ago