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Novay_Z [31]
4 years ago
8

Using pie! 3.14 calculate the areas of the circles with diameter of 21 and leave your answer in 2 demical place

Mathematics
1 answer:
galben [10]4 years ago
4 0

If we use 3.14 as pi, the areas of these circles are 415.265 square units (I recommend rounding up to 415.27 unless it says otherwise).

Step-by-step explanation:

To find the area of a circle, square the radius and multiply it by pi. To find the radius, we divide the diameter by 2 to get 11.5. Then, square 11.5 to get 132.25 and multiply by pi, or 3.14, to get 415.265, rounding up to 415.27 square units.

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Find the area of an equilateral triangle of the height of the triangle is 15cm
Gennadij [26K]

Answer:

129.9 cm^2

Step-by-step explanation:

You can use the Law of Sines to find the hypotenuse. Because it's an equilateral triangle, it's the same value for the base. If you plug in the proper angles, being 90 degrees and 60 degrees because it's an equilateral triangle, the value of the base should be 17.32050808, or 17.32 if we're rounding. If you use the usual formula for finding the area of a triangle, b * h / 2 to get an answer of 129.9 cm^2. Hope this helps and isn't too confusing! There's a bunch of lessons on Khan Academy if you need more help!

This is a bit advanced for middle school, so we might be missing some information.

7 0
3 years ago
Can you please explain how i can work through these problems?
pshichka [43]
Did you add a photo? I cant see one
3 0
3 years ago
Please someone help me...​
Savatey [412]

use a^2-b^2=(a+b)(a-b)

to get (\cos^3A-\sin^3A)(\cos^3A+\sin^3A)

then use a^3+b^3=(a+b)(a^2+b^2-ab)

and a^3-b^3=(a-b)(a^2+b^2+ab)

also, \sin^2\theta+\cos^2\theta=1

to get (\cos A-\sin A)(1+\sin A\cos A)(\cos A+ \sin A)(1-\sin A\cos A)

then again use the first identity In both pairs, i.e.

(\cos A-\sin A)(\cos A+ \sin A) \cdot (1+\sin A\cos A)(1-\sin A\cos A)

to get \cos 2A (1-\sin^2A\cos^2A)

multiply and divide by 4 to get the RHS.

because, \sin(2A)= 2\sin A \cos A

squaring both sides, \sin^2 (2A)=4\sin^2A\cos^2A

3 0
3 years ago
Read 2 more answers
(0,1) (2,3) (4,5) (3,6) (4,2) (3,9) <br> Domain <br> Range <br> Function
Wittaler [7]
Domain: 0,2,3,4
range:1,2,3,5,6,9
function: no
4 0
3 years ago
Me pueden ayudar con estos ejercicios porfa.
Ray Of Light [21]

Step-by-step explanation:

a. 3x²+10x+8 = (3x+4)(x+2)

b. 4x²+21x-18 = (4x-3)(x+6)

c. 3x²+8x+5 = (3x+5)(x+1)

d. 6x²+5x-4 = (2x-1)(3x+4)

e. 15x⁴-23x²+4 =(5x²-1)(3x²-4)

f. 15x⁴+23x²+4 =(5x²+1)(3x²+4)

g. 6x²-7x-3 = (2x-3)(3x +1)

h. 6x²-43x+72 = (3x-8)(2x-9)

7 0
3 years ago
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