[math]\frac{h _1}{84.56 cm} = tan(1.95 \times .25 \cdot 1.95) =\gt h _1 = 2.1589 cm[/math]
[math]\frac{h _2}{84.56 + d} = tan(1.95 + .25 \cdot 1.95) =\gt h _2 = .042568d + 3.599557[/math]
[math]tan \theta = \frac{2.1589 cm}{4.56 cm} =\gt 25.6^{\circ}[/math]
[math]tan \theta = \frac{h _2}{4.56 cm + d} =\gt tan (25.6^{\circ}) =\frac{.042568d + 3.599557}{d + 4.56 cm}[/math]
∴ [math]\textbf{the}[/math] [math]\textbf{thickness}[/math] [math]\textbf{of}[/math] [math]\textbf{the}[/math] [math]\textbf{lead = 3.24 cm}[/math]