Tom wants to reach a second floor window on a house that is 20 feet above ground. if he must put the ladder at a 70 degree angle. to the ground, how long must the ladder be

For this case what we should do is to see the problem as a rectangle triangle, where we have a side, an angle and we want to calculate the hypotenuse.
 We then have the following trigonometric relationship:
 sine (x) = (C.O) / (h)
 Where,
 x: angle
 C.O: Opposite leg
 h: hypotenuse
 Substituting values:
 sine (70) = (20) / (h)
 Clearing h:
 h = (20) / (sine (70))
 h = 21.28 feet
 
 the ladder must be 21.28 feet long

Ithink the answer is $2.10

3cm and 6 and 9 cm that a possibility of that question