Given that theta is a quadrant 3 angle with cos of theta=-7radical65/65, determine tan of theta

sin is - in quad 3

65^2 = 49(65) + x^2
65 (65-49) = x^2
65 (16) = x^2
x = 4 sqrt 65 (third side of triangle)
so
sin = -4 sqrt65/65

tan = sin/cos = 4sqrt65 / 7sqrt65
= 4/7