Bob is a great community member so when he sees this poor cat stuck, he knows it's up to him to save it. He is on a project to save cats like this all across the city today.
He knows that he is 5 feet from the base of the tree and his angle of elevation is 70 degrees. He knows that he is 6 feet tall. He needs to know how high up the top of the cat is so he can safely get it down. He uses trig and learns that tan(40)15= 12.6. He adds this to his height and now he knows the Cat is 18.6 feet high.
He now has his ladder. He knows that the cat is 18.6 feet in the air. He also knows his ladder is 4 feet from the base of the tree. He wants to know what the angle is at the base of his ladder and the ground. He uses trig and founds out that tanx = 18.6/4. From this he learns that the angle of his ladder and the ground is 78 degrees.