A certain LCD projector contains a single thin lens. An object 31.7 mm high is to be projected so that its upright image ?lls a screen 2.8 m high. The object-to-screen distance is 1.33 m. Find the focal length of the projection lens. Answer in units of mm. How far from the object should the lens of the projector be placed in order to form the image on the screen? Answer in units of mm