Alright so these ratios have many different forms but the way I use to remember the trigonometric ratios is:
SOH
CAH
TOA
This means:
Sine --> Opposite/Hypotenuse
Cosine --> Adjacent/Hypotenuse
Tangent --> Oppositie/Adjacent
With that in mind, number 1:
Would be Sine, or C.
Number 2 would be, Cosine, or E.
And number 3 would be Tangent, or B.
Hope that was helpful.
It'd look like this as an equation:
3h-8
Simple, just divide the number by the percentage and you get the original number. You can check it by multiplying the original number of 272 by 55% or .55 to get 150.
150/.55 = 272
Answer: 65.94 square meters
This value is approximate since pi = 3.14 is approximate
------------------------------------------------------------------
Work Shown:
Area of circle = pi*(radius)^2
A = pi*r^2
Area of smaller circle = pi*2^2 <<--- replace r with 2; which is the smaller radius
Area of smaller circle = 4*pi
Area of larger circle = pi*5^2 <<--- replace r with 5 (since 3+2 = 5); which is the larger radius
Area of larger circle = 25*pi
Area of shaded region = (area of larger circle)-(area of smaller circle)
Area of shaded region = 25*pi - 4*pi
Area of shaded region = 21*pi
Area of shaded region = 21*3.14 <<--- replace pi with 3.14 (approximate)
Area of shaded region = 65.94 square meters