Bobby should grow an amount greater than 70-61 = 9 inches to become taller than 70 inches. Therefore, the correct answer is that Bobby must grow an amount of x> 9 inches to be taller than 70 inches.
factor 9 out of the equation
18x^6 / 27x^4 becomes
2x^6 / 3x^4
cancel out common factors to get
2x^2/3
Given the radius of the inscribed circle, the length of any side of the octagon (and any other polygon) is given by;
Side = 2r* tan (180/n) where r=radius and n=number of sides.
For octagon, n= 8 and radius is given by , r= 7/2 = 3.5 ft
Therefore,
Side = 2*3.5*tan (180/8) 2.8995 ft =2.9 ft.
The correct answer is A.
