ElectricPavlov

h = 8.7 m

8.7 = -4.9t^2 + 14 t -.4

0 = -4.9 t^2 + 14 t - 9.1         Now use Quadratic Formula to solve for t's    the time above 8.7 m is the time between the t's

         a = -4.9     b = 14     c = - 9.1

\(t = {-14 \pm \sqrt{(14)^2-4(-4.9)(-9.1)} \over 2(-4.9)}\)

60 min / hr * 1/4 hr   = 15 min

y = k/x²           k = proprtionality constant

y x^2 = k

27 (6²) = 972  

now when y = 8

8 (x²) = 972

x = +sqrt(121.5)

Assuming there are 10 digits possible for each spot in the combo

10 * 9 * 8 * 7 * 6 = 30 240 possible combinations     you have a   1 / 30,240   chance of guessing on your first try

Vertex (-4,0) form of parabola

y= a ( x- - 4)^2 + 0

  y = a (x+4)^2       sub in the point 7,1

  1 = a (7+4)^2   

        so a = 1/121

x 0 x     =   9 * 9 = 81

x x 0     =   9 * 9 = 81        summed = 162 possibles

Change B to   -5, 7    to make a square

find distance between A and B to find side length

  = sqrt ( 74)         then the area  =  s * s  = 74 units2

840       arithmetic series   d = 4

842      geometric series   r = 1/2

840 is the original number

AB = 5       ra + rb = 5            (ra = radius of circle 'a'   etc)

AC = 6       ra + rc = 6

BC = 8       rb + rc = 8        

solve for the radii then you can comput the areas

ra = 5 - rb    sub into second equation

5-rb + rc = 6      multiply   eq 3  by -1   and add to this equation to get:

5 - 2 rb = -2

rb = 3.5     the ra = 1.5     rc =4.5    <============Take it from here !

p + j = 924 (2) = 1848

p = j + 232         so p = 1040     and j = 808

a = p + 172 = 1212

j / a = 808 / 1212   = 2/3