In a large mixing bowl, whisk together flour, baking powder, salt, and sugar until no lumps remain. Use a pastry cutter to cut the butter into the mixture. Stir in cheese, bacon, and green onions. Stir in 3/4 cup milk until combined. Tranfer to a well floured surface and pat into a large circle, about 3/4-inch thick. Transfer to your prepared baking sheet and cut into 8 triangles. Separate the triangles slightly and brush with a bit of milk to help them brown.