How do you find the area of this trapezoid

The amount of money, in dollars, in an account after t years is given by a = 1000(1.03)^t. the initial deposit into the account was $_^a0 and the interest rate was _a1% per year. only enter numbers in the boxes. do not include any commas or decimal points^t. the initial deposit into the account was $__^a0 and the interest rate is % per year.

Plz hurry evaluate the expression a+b where a=8 and b=19

Which situation is an example of an observational study?