Dragan

57 : 100% = X : 95%        X = 54.15

Discounted price will be  $ 54.15  +tax  

Proportions:      2 : 3 = 18 : X     X = 3 * 18 / 2      X = 27

                         3 : 2 = 18 : Y     Y = 2 * 18 / 3      Y = 12    

She pays  $149.4 per month. She's  lucky

The area of the shaded region    A_s = π - [ π/2 + 1 - 2( π/4 - 1/2 )]    

Area of hexagon  ABCDEF ≈ 39.84 u²     or     Area = sqrt(3) * 23    

I'll try numbrrer 5;    this one's a bit tricky

  Important: In a proportion "Total" is always 100%  and  "Part" can be any number, including 100 and larger             

 Question:    15 is what percent of 5 ?

 Part  =   15

 Total =    5  (100%)

  Percent  = ?              5 : 100%  =  15 : X      X = (100% * 15) / 5    X = 300% 

  Answer:   15 is 300% of 5.        

∠ BAC = 120°             The law of cosines:      a² = b² + c² - 2ab * cosA  

AC = 150                         (BC)² = (AB)² + (AC)² - 2(AB)(AC) * cos(BAC) 

AB = 300                                                        BC = 396.86      

I was looking for the angle whose cosine value is for 2 units larger then the value of sine.

And these numbers popped up:    0.8 and 0.6        sin(36.87°) = 0.6     cos(36.87°) = 0.8

I multiplied these numbers by 10,  and got the sides of a rectangle: a = 6   and  b = 8

Diagonal   d = r                      r² = a²+ b²           r = 10      

Your concept is good, but the answer is wrong!

You did not subtract the area of a triangle  CDG.

The area of AFD = 4 cm²