Find the centre of the gravity of a uniform plate in the form of a symmetrical trapezium whose parallel sides are 3 meters and 1.5 meters in length and 2 meters apart. If it has rectangular extension of the same weight per square meter attached to the 1.5 meters edge and y meters long so as just to fit that edge, find what should be the height y of the rectangular piece if the centre of gravity of the whole is on the 1.5 meter edge of the trapezium. (a) 11.11 m, 2.58 m (b) 1.67 m, 2.58 m (c) 1.11 m, 1.67 m (d) 1.67 m, 1.11 m