Why do objects further away appear smaller?

This is because as the object gets further away, the image shrinks because the vertical and horizontal coordinates become smaller as z increases. If you think about it visually, the angles decrease and the point q grows closer to the x-axis.

Why do objects further away appear smaller?

This is because as the object gets further away, the image shrinks because the vertical and horizontal coordinates become smaller as z increases. If you think about it visually, the angles decrease and the point q grows closer to the x-axis.