Melody

This is not 4 digits.

this has been answered recently. Go look for it.

It could be

13^2 = 169

or

14^2=196

I think they both meet all the requirements

How did you come up with those Alan?  

Is there some technique you can show us?

You got it   

Thanks catmg

Use a contour probability map to solve.

Area of little (desirable ) triangle = 0.5

Area of large (sample space) triangle = 0.5*5*5 = 12.5

probability of  that the yare all less than 2 units =  0.5 / 12.5  = 5/125  = 1/25   or  0.04   or  4%

This was answered yesterday or the day before.  Go look for it.

if the angle is acute then

sin(x)=cos(pi/2 - x)

You can draw a right-angled triangle to convince yourself that this is true.

use that.