Lets get started :)
The First question:
Diameter = 20 ft
Radius =

of 20 (diameter) = 20 ft
Area formula of a circle is
A =

r²
=

(10)²
=100

ft²
≈ 314 ft²The answer will be the second optionThe Second question:
radius of circle = 12mm divided into 20 sectors area
A =

r²
=

(12)²
= 144

ft²
Divide into 20 equal sector areas =
≈ 22.6 mm²Your answer will be the third optionThe Third Question:
90°, sector area = 36

, Radius = ?



and

cancels out
We can now cross multiply
360 × 36 = 90r²
12960 = 90r²
Divide by 90 on either side

144 = r²
Take squareroot
x = 12 inYour answer will be the third option
The answer is 10/3. Because you have 3 wholes and 1/3 so, 3x3 is 9 and you still have the extra 1 so 9+1=10 therefore your answer would be 10/3
Step-by-step explanation:
sin(2x) = 2sin(x)cos(x)
2sin(x)cos(x) - cos(x) = 0
so one solution is cos(x) = 0.
=> x = pi/2 and 3pi/2 (90° and 270°)
for cos(x) <> 0 we have then
2sin(x) - 1 = 0
2sin(x) = 1
sin(x) = 1/2
=> x = pi/6 and 5pi/6 (30° and 150°)