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3 years ago

Need help in geometry right answers only please give me now 25 points

Mathematics

2 answers:

photoshop1234 [79]3 years ago

5 0

The area of the circle = π r² = π (d/2)²
Where r is the radius of the circle
And d is the diameter of the circle
d = 2r OR r = d/2
given d = 10 in ∴ r = d/2 = 10/2 = 5 in
∴ The area of the circle = π r² = π * 5² = 25π ≈ 78.54 in²

The correct answer is the fourth option 78.54

==========================================
very important note:
There is a mistake in the dimension of the answers.
The dimension of the given diameter is inch , while the dimensions of the answers is square cm.

If it is required to find the area in square cm
∵ 1 inch = 2.54 cm
∴ r = d/2 = 10/2 = 5 in = 5 * 2.54 cm = 12.7 cm

∴ Area = π r² = π * (12.7)² = 161.29π ≈ 506.7 square cm

dezoksy [38]3 years ago

5 0

What is the area of a circle with a diameter measuring 10 inches?
31.4 square cm
81.41 square cm
153.93 square cm
78.54 square cm

In solving this problem, let us recall the formula for the area of a circle:
We know that the formula for the area of a circle is given by:
A= (pi)(r^2)

Since in this problem, the diameter is given by 10 inches:
But diameter= radius(r) times 2
D= 2r
Thus;
r=5 inches

Substitute:
A= (pi)(5^2)
A=78.54 square inches

Convert inches to cm since the choices are in cm:
1 inch= 2.54 cm

78.54 inches(2.54 cm/1 inch)
A=199.49 square cm

Since the correct answer is not in the given choices, it can be assumed that the choices have a wrong label/unit. We can then say that the correct answer should be:

A=78.54 square inches
or
A=199.49 square cm

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3 years ago

Which ordered pair is a solution to the linear inequality below?

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Answer:

Step-by-step explanation:

The inequality is

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You can substitute each of the choices in the inequality (on the left side) to see if the result is >=10.

A: 3(1)-5(4)=3-20=-17 not good.

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3 years ago

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Lin created a scaled copy of Triangle A with an area of 72 square units. How many times larger is the area of the scaled copy co

Tju [1.3M]

Answer:

Copy's area is 16 times bigger then triangle area.

Step-by-step explanation:

Given:

Area of copy = 72 unit²

Find:

How bigger copy compared to triangle

Computation:

Area of triangle = [1/2][base][height]

Area of triangle = [1/2][3][3]

Area of triangle = 4.5 unit²

So.

Area of copy / Area of triangle

72 / 4.5

So,

Copy's area is 16 times bigger then triangle area.

3 0

3 years ago

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fomenos

Answer: drag the first one to the fourth one, drag the second one to the first one,drag the third one to the second one,drag the fourth one to the third one.

Step-by-step explanation:if its wrong then im sorry

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3 years ago

Cos pi/4 cos pi/6= 1/2(___pi/12+cos 5pi/12) fill in the blank

inessss [21]

Answer:

$\cos(\frac{\pi}{4})\cos(\frac{\pi}{6})=\frac{1}{2}(\cos(\frac{\pi}{12})+\cos(\frac{5\pi}{12}))$

So the blank is cos.

Step-by-step explanation:

There is an identity for this:

$\cos(a)\cos(b)=\frac{1}{2}(\cos(a+b)+\cos(a-b))$

Let's see if this is fit by your left hand and right hand side:

So $a=\frac{\pi}{4}$ while $b=\frac{pi}{6}$ .

Let's plug these in to the identity above:

$\cos(\frac{\pi}{4})\cos(\frac{\pi}{6})=\frac{1}{2}(\cos(\frac{\pi}{4}+\frac{\pi}{6})+\cos(\frac{\pi}{4}-\frac{\pi}{6}))$

Ok, we definitely have the left hand sides are the same.

Let's see if the right hand sides are the same.

Before we move on let's see if we can find the sum and difference of $\frac{\pi}{4}$ and $\frac{\pi}{6}$ .

We will need a common denominator. How about 12? 12 works because 4 and 6 go into 12. That is 4(3)=12 and 6(2)=12.

$\frac{\pi}{4}+\frac{\pi}{6}=\frac{3\pi}{12}+\frac{2\pi}{12}=\frac{5\pi}{12}$ .

$\frac{\pi}{4}-\frac{\pi}{6}=\frac{3\pi}{12}-\frac{2\pi}{12}=\frac{\pi}{12}$ .

Let's go back to our identity now:

$\cos(\frac{\pi}{4})\cos(\frac{\pi}{6})=\frac{1}{2}(\cos(\frac{\pi}{4}+\frac{\pi}{6})+\cos(\frac{\pi}{4}-\frac{\pi}{6}))$

$\cos(\frac{\pi}{4})\cos(\frac{\pi}{6})=\frac{1}{2}(\cos(\frac{5\pi}{12})+\cos(\frac{\pi}{12}))$

We can rearrange the right hand side inside the ( ) using commutative property of addition:

$\cos(\frac{\pi}{4})\cos(\frac{\pi}{6})=\frac{1}{2}(\cos(\frac{\pi}{12})+\cos(\frac{5\pi}{12}))$

So comparing my left hand side to their left hand side we see that the blank should be cos.

4 0

3 years ago