The numbers would be -0.9 and 1.7
        
                    
             
        
        
        
Answer:
3
Step-by-step explanation:
P is the in-center
⇒PA=PE=PD because they are in-radius of the in-circle
We know that, tangent segments drawn from a point outside the circle are always equal in length
⇒DK=EK=7.2
In right triangle PKE,
using Pythagoras' Theorem : 
⇒
⇒
⇒
⇒
Therefore, 
 
        
             
        
        
        
I'm assuming the funds earn 5% yearly?
Call x the amount he saves every year.  The first year's deposit will be multiplied by 1.05 three times, the next will be multiplied by 1.05 twice, the third will be multiplied by 1.05 once, and the fourth will not generate interest (as it will immediately be used to buy the car).
Therefore, x(1.05^3+1.05^2+1.05+1)=21000, so 4.31x=21000.  Dividing by 4.31, we see that x is approximately equal to 4872.