If the cos of an angle is positive, the angle will be in either the first quadrant or the fourth quadrant.
If the csc of an angle is negative (since csc = 1/sin), the sin will also be negative and the sin is negative in either the third quadrant or the fourth quadrant.
Since cos(t) = 4/7 and csc(t) < 0, tthe angle t must be in the fourth quadrant.
Since cos = x/r and cos(t) = 4/7, x = 4 and r = 7.
Using the Pythagorean Theorem: x2 + y2 = r2 ---> 42 + y2 = 72 ---> 16 + y2 = 49 ---> y2 = 33
So, either y = sqrt(33) or y = - sqrt(33).
Since the angle is in the fourth quadrant: y = -sqrt(33).
sin = y/r ---> sin(t) = -sqrt(33) / 7
tan = y/x ---> tan(t) = -sqrt(33) / 4