Matrix Dimensions must agree GUI

I am creating a projectile motion GUI. I keep running into Matrix dimesion must agree for x and y values.

            theta=app.ThetaEditField.Value; 
            v0=app.InitialVelocityEditField.Value; 
            g=9.81; 
            ax=0;
            ay=-g; 
            vix=v0*cosd(theta); 
            viy=v0*sind(theta); 
            vfx=vix; 
            vfy=-viy; 
            t=(vfy-viy)/ay; 
            t2 = 0 : t/100 : t*2;
            
            x=vfx.*t2+(1/2)*ax.*t2.^2; 
            y=viy.*(t2./2)+(1/2)*(ay).*(t2./2).^2 ;

[VBBV]

It could also be possible if you are using theta and v0 variables elsewhere in your GUI functions

Use

clear theta v0

variables before using them in GUI function

Are you trying to enter theta and v0 as vectors ? or scalar