Answer:
I hope my drawing explains well lol... h = 16
Step-by-step explanation:
So basically first you need to find x (the one in the drawing), by doing so, you just have to use the formula,
[tex]speed = \frac{distance}{time} [/tex]
You substitute in the speed and the time given,
[tex]0.4 = \frac{x}{30} \\ x = 12[/tex]
Then, you use the Pythagorean theorem,
[tex] h = \sqrt{ {20}^{2} - {12}^{2} } \\ h = 16 [/tex]