Solve function not working

Hi everyone, I'm really new to Matlab and am struggling to get this code to work, I was hoping for the Wall_thickness and Outer_Diameter variables to output numbers but I've been unsuccessful. Any ideas?

%% Parameters
Outer_Diameter = 2;
Unit_Cell_Size = 4;
Material_Density = 4.41;
Lattice_Density = 2.8;
%% Calculations
Mass = Lattice_Density*((0.1*Unit_Cell_Size)^3);
Unit_Cell_Volume_cm = Mass/Material_Density;
Unit_Cell_Volume_mm = Unit_Cell_Volume_cm/0.001;
syms Wall_thickness Outer_Diameter
Equation1 = ((pi*(Outer_Diameter/2)^2)*Unit_Cell_Size)-((pi*(Outer_Diameter/2)^2)*Outer_Diameter);
Equation2 = ((pi*((Outer_Diameter/2)-Wall_thickness)^2)*Unit_Cell_Size)-((pi*((Outer_Diameter/2)-Wall_thickness)^2)*(Outer_Diameter-(2*Wall_thickness)));
solve(Equation1,Equation2);

Answer 1

[Walter Roberson]

%% Parameters
Outer_Diameter = 2;
Unit_Cell_Size = 4;
Material_Density = 4.41;
Lattice_Density = 2.8;
%% Calculations
Mass = Lattice_Density*((0.1*Unit_Cell_Size)^3);
Unit_Cell_Volume_cm = Mass/Material_Density;
Unit_Cell_Volume_mm = Unit_Cell_Volume_cm/0.001;
syms Wall_thickness Outer_Diameter
Equation1 = ((pi*(Outer_Diameter/2)^2)*Unit_Cell_Size)-((pi*(Outer_Diameter/2)^2)*Outer_Diameter);
Equation2 = ((pi*((Outer_Diameter/2)-Wall_thickness)^2)*Unit_Cell_Size)-((pi*((Outer_Diameter/2)-Wall_thickness)^2)*(Outer_Diameter-(2*Wall_thickness)));
sol = solve(Equation1,Equation2);

sol.Outer_Diameter

ans = 

sol.Wall_thickness

ans = 

[Joirdan Noronha]

Sorry Walter I just some of the section, however the sol. function isnt working

clc, clear
%% Cubic Unit Cell Equation
%% Parameters
Unit_Cell_Size = 4;
Material_Density = 4.41;
Lattice_Density = 2.8;
%% Calculations
Mass = Lattice_Density*((0.1*Unit_Cell_Size)^3);
Unit_Cell_Volume_cm = Mass/Material_Density;
Unit_Cell_Volume_mm = Unit_Cell_Volume_cm/0.001;
syms Outer_Diameter Wall_thickness
Equation1 = Unit_Cell_Volume_mm == 2*(((pi*(Outer_Diameter/2)^2)*Unit_Cell_Size)-((pi*(Outer_Diameter/2)^2)*Outer_Diameter)-((pi*((Outer_Diameter/2)-Wall_thickness)^2)*Unit_Cell_Size)-((pi*((Outer_Diameter/2)-Wall_thickness)^2)*(Outer_Diameter-(2*Wall_thickness))))+(((pi*(Outer_Diameter/2)^2)*Unit_Cell_Size)-((pi*((Outer_Diameter/2)-Wall_thickness)^2)*Unit_Cell_Size));
Equation2 = ((pi*(Outer_Diameter/2)^2)*Unit_Cell_Size)-((pi*(Outer_Diameter/2)^2)*Outer_Diameter);
Equation3 = ((pi*((Outer_Diameter/2)- Wall_thickness)^2)*Unit_Cell_Size)-((pi*((Outer_Diameter/2)- Wall_thickness)^2)*(Outer_Diameter-(2*Wall_thickness)));
sol = solve(Equation1,Equation2,Equation3);
sol.Equation1
sol.Equation2
sol.Equation3

[Joirdan Noronha]

I'm weirdly getting this response

ans =

Empty sym: 0-by-1

ans =

Empty sym: 0-by-1

[Walter Roberson]

Unit_Cell_Size = 4;
Material_Density = 4.41;
Lattice_Density = 2.8;
%% Calculations
Mass = Lattice_Density*((0.1*Unit_Cell_Size)^3);
Unit_Cell_Volume_cm = Mass/Material_Density;
Unit_Cell_Volume_mm = Unit_Cell_Volume_cm/0.001;
syms Outer_Diameter Wall_thickness
Equation1 = Unit_Cell_Volume_mm == 2*(((pi*(Outer_Diameter/2)^2)*Unit_Cell_Size)-((pi*(Outer_Diameter/2)^2)*Outer_Diameter)-((pi*((Outer_Diameter/2)-Wall_thickness)^2)*Unit_Cell_Size)-((pi*((Outer_Diameter/2)-Wall_thickness)^2)*(Outer_Diameter-(2*Wall_thickness))))+(((pi*(Outer_Diameter/2)^2)*Unit_Cell_Size)-((pi*((Outer_Diameter/2)-Wall_thickness)^2)*Unit_Cell_Size));
Equation2 = ((pi*(Outer_Diameter/2)^2)*Unit_Cell_Size)-((pi*(Outer_Diameter/2)^2)*Outer_Diameter);
Equation3 = ((pi*((Outer_Diameter/2)- Wall_thickness)^2)*Unit_Cell_Size)-((pi*((Outer_Diameter/2)- Wall_thickness)^2)*(Outer_Diameter-(2*Wall_thickness)));
sol = solve(Equation1,Equation2)

sol = struct with fields:
    Outer_Diameter: [6×1 sym]
    Wall_thickness: [6×1 sym]

E3 = subs(Equation3, sol)

E3 = 

vpa(E3)

ans = 

You have three equations in two variables. If you solve the first two equations for the two variables, and substitute those into the third equation, none of the possibilities solve the third equation.

There is no combination of the two variables that can solve all three equations at the same time.