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3 years ago

Pls answer Question 28 and 29 asap.

Mathematics

1 answer:

Kaylis [27]3 years ago

4 0

28. Answer: 86% decrease

Step-by-step explanation:

Original Sphere has a radius of 100% → r =1

Surface Area of Original Sphere:

S.A. = 4πr²

= 4π(1)²

= 4π

New Sphere has a diameter of 75% → d = 0.75 → r = 0.375

Surface Area of New Sphere:

S.A. = 4πr²

= 4π(0.375)²

= 0.5625π

$\text{\% Change} =\dfrac{New - Original}{Original}\\\\.\qquad \qquad =\dfrac{0.5625\pi -4\pi}{4\pi}\\\\.\qquad \qquad =\dfrac{-3.4375\pi}{4\pi}\\\\.\qquad \qquad =-0.86$

The negative sign represents a decrease.

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29. Answer: 72 bottles

Step-by-step explanation:

Volume of a hemisphere is:

$V=\dfrac{2}{3}\pi r^3\\\\.\quad =\dfrac{2}{3}\pi (18)^3\\\\.\quad = 3888\pi$

Volume of a cylinder is:

$V=\pi r^2h\\\\.\quad =\pi (3)^2(6)\\\\.\quad =54\pi$

The number of cylinders needed is:

$\dfrac{3888\pi}{54\pi} = 72$

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Zina [86]

Answer:

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3 years ago

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Neko [114]

Hi :)
the correct answer is J
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3 years ago

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madam [21]

Answer:

-3

Step-by-step explanation:

-3/8÷3/4

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3 years ago