The tree, bamboo pole and the ground will form a right triangle. the length of the pole is the hypotenuse of the right triangle form. so it can be solve using: sin A = o / h where A is the angle o is the oposite side of the angle h is the hypotenuse
h = o / sin a h = 12.2 / sin 40 h = 18.7 m is length of the pole