Question

PLEASE HELP?

Answer 1

I got `15.8cm`

Explanation:

If AB and BC are tangent they should form an angle of `90^@` with the radius:

Using trigonometry I can analize the triangle AOB and find angle `alpha` by writing:

`4=10cos(alpha)`

so that:

`alpha=arcos(4/10)=66.4^@`
so that the total angle will be:

`2alpha=132.8^@`

the angle `theta` will be:

`theta=360^@-132.8^@=227.2^@` corresponding to `3.96` radians

the arc length `s` will be (angle in radians):

`s=rtheta=4*3.96=15.8cm`