Question

How do I do this, is the equation 40=ksqrt(65)?

Answer 1

Explanation:

Start a little more generally. Carefully find k

distance = k * speed ^2

112 = k*40^2

112 = k * 1600 Divide by 1600

112/1600 = k

k = 0.07

Now do the question you are asked to do.

distance = k * speed^2

distance = 0.07 * 65^2

distance = 295.75

Now having done that, you can set up a proportion.

d1 / d2 = k speed1^2/kspeed2^2 Cancel the ks

112/d2 = 40^2 / 65^2 Cross multiply

112 * 65^2 = 40^2 * d2 Divide by 40^2

112 * 65^2/40^2 = d2 Expand the squares

112 * 4225 / 1600 = d2

295.75 = d2

The second way is shorter, but I suggest the long way until you get comfortable with it.