The answer depends on
The part of the calculator that is defected
- The circuitry (unlikely as it can be turned on)
- The buttons (some of them)
- The display (assuming 7-segment LCD)
How you tried to find the area and radius of a circle
- Starting with the radius, $\pi r^2 = A$
- Starting with the area, $\sqrt{A/\pi}=r$
As none of this specified in the question, the following will only consider the display being defected and try to address both cases of the calculation.
Case 1: $\pi r^2 = A$
It could be that only the last digit (units location) of the seven segment display is working. So, assuming you enter $r=20153$ as the radius, you could only see the last number, $3$. Typing the rest of the formula should yield $1275937150.0183146$, i.e., $1275937150$ on a 10-digit seven segment display from which you could only see the last digit, $0$.
Case 2: $\sqrt{A/\pi}=r$
It could be that only the first digit of the seven segment display is working and the rest just shows nothing (as opposed to a zero). So, assuming $A=31.4$, you could have tried to type the number and ended up seeing nothing then the rest of the calculation is supposed to give you $3.161475988...$ and since only the first digit is working, you get to only see 3; the rest of the decimal digits of the calculator shows nothing.