1920x1080 = 2073600 pixels
3840x2160 = 8294400 pixels
8294400 / 2073600 = 4
Because you're doubling both the horizontal and the vertical it's 4x bigger in area.
You can look at it the same way with smaller numbers. You have a rectangle which is 3cm long and 2cm wide. 3x2 = 6 square cm. If you double the rectangles sides to 6cm and 4cm. 6x4 = 24 square cm. So in area it's 4x larger.
3840x2160 = 8294400 pixels
8294400 / 2073600 = 4
Because you're doubling both the horizontal and the vertical it's 4x bigger in area.
You can look at it the same way with smaller numbers. You have a rectangle which is 3cm long and 2cm wide. 3x2 = 6 square cm. If you double the rectangles sides to 6cm and 4cm. 6x4 = 24 square cm. So in area it's 4x larger.
Last edited: