<span>First of all, there should be coherence for the units of measurement -- either they are all meters or they are all ft. I would assume they are all ft.
The correct answer is 75 ft above. T
The explanation is the following: suppose the ground level is the x-axis, the 2 feet of the arch lie respectively on (0,0) and (100,0) on the ground level. Since the arch is 100ft high, the vertex of the parabola will be the point (100,100). Thus, we can find the equation describing the parabola by putting the three points we know in a system and we find that the equation of the parabola is y=(-1/100)x^2+2
To find the focus F, we apply the formula for the focus of a vertical axis parabola, i.e. F(-b/2a;(1-b^2+4ac)/4a).
By substituting a=-1/100, b=2 and c=0 into the formula, we find that the coordinates of the focus F are (100,75).
So we conclude that the focus lies 75ft above ground.</span>
Answer:
C. 12
Step-by-step explanation:
With the rule of 72, you would divide 72 by the periodic interest rate to get the number of years for the principal to double
72 ÷ 6 = 12
Answer:
6 different primes.
3, 7, 13, 29, 31 , 89.
Step-by-step explanation:
Try dividing by primes starting with 3:
3 ) 65529009
3 ) 21843003
7) 7281001
13) 1040143
29) 80011
31 ( 2759
89. 89 is a prime number.
