U should do like this... But sry I don't know third part
We will have to use the formula for the area of a trapezoid on this problem, which is (
and
are the bases of the trapezoid and
is the height):

All we need to do is substitute the information we are given into our formula:

Now, let's just simplify the equation:




The missing base has a length of 13 units.
Answer & Step-by-step explanation:
In the problem, we are given an equation. h(t) = -20 + 11t
In the equation, t represents an unknown value. So, if we are given a number that is in the replacement of t, then we can plug that number in to where t is at.
t = 11
h(11) = -20 + 11(11)
h(11) = -20 + 121
h(11) = 101
So, h(11) is equal to 101