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3 years ago

Find the area of a semi-circle withdiameter d cm.

Mathematics

1 answer:

siniylev [52]3 years ago

6 0

Answer:

I will let you answer this after reading below

Step-by-step explanation:

a=area

$a = \pi {r}^{2}$

$r = d \div 2$

write a in terms of d

$a = \frac{\pi {d}^{2}}{ 4}$

since it's a semicircle divide a by 2 and that's your answer

I can confirm you answer if you like in a comment

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What is the size of ∠ ABC shown in the above figure

SIZIF [17.4K]

A. thirty-five degrees

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3 years ago

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Craign has a building block in the shape of a rectangular pyramid .A net of which is shown below.If a measures 12 cm b measures

svetoff [14.1K]

Answer:

<h3>Option D) 294 sq cm is correct</h3><h3>∴ the surface area of the rectangular pyramid is 294 sq cm</h3>

Step-by-step explanation:

First we have to split the net into 4 triangles and 1 rectangle

Given a = 12 cm ,b = 6 cm and d = 13 cm

<h3>To find the surface area of the rectangular pyramid:</h3>

Now find the area of the rectangle base

$Rectangle base area=b\times a$

$= 6\times 12$

= 72 sq. cm

<h3>∴ Rectangle base area=72 sq cm</h3>

Now to find the area of the triangle on the left

$Left triangle=\frac{1}{2}(b)(d)$

$=\frac{1}{2}(6)(13)$

= 39 sq cm

<h3>∴ Left triangle=39 sq cm</h3>

Since all the triangles are congruent , you will need to multiply by 2 to get the combined area of the triangle on the left and on the right.

Area of left and right triangles= 2(39)

=78 sq cm

<h3>∴ Area of left and right triangles=78 sq cm</h3>

Find the area of the triangle on the bottom

$Bottom triangle area=\frac{1}{2}(a)(a)$

$=\frac{1}{2}(12)(12)$

= 72 sq cm

<h3>∴ Bottom triangle area=72 sq cm</h3>

Since the bottom of the triangle is congruent to the top triangle, multiply that by 2 to get a combined area of the triangle on the bottom and top

Area of top & bottom triangles=2 (72)

= 144 sq cm

<h3>∴ Area of top & bottom triangles= 144 sq cm</h3>

Finally add the area of the 4 triangles to the area of the rectangular base we get

=72 + 78 + 144

= 294 sq cm

<h3>∴ the surface area of the rectangular pyramid is 294 sq cm</h3><h3>∴ option D) 294 sq cm is correct.</h3>

7 0

3 years ago

Help me and thank you

uysha [10]

I believe it’s (b) I think

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2 years ago

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I need help on one of my math questions. It would be most helpful to get the answer as well as an explanation on how to do these

svlad2 [7]

This is a very interesting problem. What makes it so interesting is that
there's so little actual math to it. The only big Math thing you need to know
in order to work with this question is the definition of "perimeter".

"Perimeter" means

"the distance all the way around the edge of something".

The problem GIVES you the length of all the sides of both triangles.
To find the perimeter of one triangle, just take the lengths of its three
sides and addum up.

The perimeter of the blue one is (7x+7) + (5x-4) + (4x+2) .
That's it ! That's the perimeter. Of course, they want you to write
it in simplest form, so you have to clean it up. Remove all of the
parentheses, add up all the 'x's, and add up all the plain numbers,
and you'll have a short, pretty expression.

Then do the same thing for the red one, and get its perimeter.

In part-b, they want you to find the difference between the two perimeters.
No problem. Just write (the blue perimeter) minus (the red perimeter),
and simplify THAT expression.

Now they want the actual perimeters when 'x' is 3.
No big deal. Just take each separate perimeter, write '3' in place of 'x',
and find the number that the expression becomes.

Just now, looking at the picture without writing anything down,
I got 53 for the blue one and 17 for the red one.
I could easily be wrong, so you definitely have to work them
out for yourself.

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3 years ago

|a−b| − |c+d| , if a=−5; b=4; c=1; d=−3

Licemer1 [7]

Answer:

Step-by-step explanation:

|a−b| − |c+d| , if a=−5; b=4; c=1; d=−3

= a + b - c + d

= 5 + 4 - 1 + (-3)

= 5 + 4 - 1 - 3

= 5 + 4 - 4

= <em><u>5</u></em>

4 0

3 years ago

Find the area of a semi-circle withdiameter d cm.​

Find the area of a semi-circle withdiameter d cm.