I have a random seven digit number. What's the probability of it having 3 zeros and 4 ones ???

Really need on these. i have no idea what to do

Suppose a triangle has two sides of length 32 and 35, and that the angle between these two sides is 120°. which equation should you solve to find the length of the third side of the triangle?

Which set of reflections would carry trapezoid abcd onto itself? a) x-axis, y=x, y-axis, x-axis b) x-axis, y-axis, x-axis c) y=x, x-axis, x-axis d) y-axis, x-axis, y-axis, x-axis