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ad-work [718]
3 years ago
5

Please help! The following three shapes are based only on squares, semicircles, and quarter circles. Find the perimeter and the

area of each shaded part.

Mathematics
1 answer:
Rama09 [41]3 years ago
7 0

Answer:

perimeter = (18 +9π) cm

area = (81 -20.25π) cm^2

Step-by-step explanation:

The perimeter of the shaded area is the circumference of the circle added to two sides of the square. The circumference of the circle is π times the diameter, so the perimeter is ...

p = 2(9 cm) + π(9 cm) = (18 +9π) cm

___

The area of the shaded portion is the difference between the area of the square and the area of the circle. The area of the square is the square of the diameter. The area of the circle is π/4 times that value.

A = (9 cm^2) + (π/4)(9 cm^2) = (81 +20.25π) cm^2

_____

Comment on circle area

The formula you often see is ...

A = πr^2 . . . . r is the radius

since r = d/2, where d is the diameter, this can also be written as ...

A = π(d/2)^2 = (π/4)d^2

Here, the diameter of the circle is the same as the side length of its enclosing square, so the area of the circle is π/4 times the area of the enclosing square.

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A black bear has a mass of about 135 kg which is the best estimate of the mass of 3 black bears
sasho [114]

Answer:

405 kg

Step-by-step explanation:

135 times 3 equals 405

Hope this helps!

7 0
3 years ago
Read 2 more answers
Callum is walking 270 miles to raise money for cancer research. He plans to walk 1/9 of the distance each day. After 7 days, how
Dmitry_Shevchenko [17]
270-(7/9x270)=60miles
7 0
3 years ago
Harper is working two summer jobs, making $19 per hour lifeguarding and making $8 per hour walking dogs. In a given week, she ca
ohaa [14]

Answer:

We know that:

She makes $19 per hour of lifeguarding.

She makes $8 per hour walking dogs.

She can work at most 7 hours per week.

She must earn a minimum of $80 per week.

If x represents the number of hours lifeguarding and y represents the number of hours walking dogs, the inequalities will be:

x + y ≥ 7 hours.

(this says that she can work at most 7 hours per week)

x*$19 + y*$8 ≥ $80

(this says that she can earn a minimum of $80)

Then the system of inequalities is:

x + y ≥ 7 hours.

x*$19 + y*$8 ≥ $80

To graph these two we can write them as lines in standard form and simply graph both inequalities, the solution of the system will be the intersection between the solutions of each inequality.

Here we also should add the inequalities:

x ≥ 0

y ≥ 0

So we only look at the first quadrant.

The graph can be seen in the image below: (the dark blue is the solution region for the first inequality, the light blue one is the solution region for the second inequality)

 

One possible solution can be:

x = 4 and y = 1

or

x = 4 and y = 2

and there are a lot of other possible solutions.

5 0
3 years ago
The diagram shows a solid which is half of a cone. Calculate the total surface area of the solid.
Vilka [71]

Answer:

<h2>100πcm².</h2><h2>None of the options is correct</h2>

Step-by-step explanation:

Total surface area of a cone S = \pi r^{2}+\pi  rl\\

Since the diagram is half of a cone, its surface area will be S = \frac{\pi r^{2} +\pi rl}{2}

r = radius of the cone

l = slant height

From the diagram diameter of the cone = 16m;

r = 16/2 = 8m

l = 17m

S = \frac{\pi (8)^{2} +\pi (8)(17)}{2}\\S = \frac{64\pi + 136\pi }{2} \\S = 32\pi + 68\pi \\S = 100\pi cm^{2}

5 0
3 years ago
A full moon occurs about every 30 days . If the last full moon occurred on a Friday, how many days will pass before a full moon
pentagon [3]
The answer is 30 days until it appears on a Friday again. In order to see the full moon again, we have to go through the entire cycle. So, it will be about 30 days before we would have seen another one. 
7 0
3 years ago
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