Q14Short answerExercise 12.2
cm. Find the surface area of the cone and of the remaining solid left out after the cone carved out. Solution : The cone of maximum size that is carved out from a cube of edge 14 cm will be of base radius 7 cm and the height 14 cm. Surface area of the cone = πrl + πr2 22 22 = × 7 × 7 2 +142 + (7)2 7 7 22 2 = 7 × 7 × 245 + 154 = (154 5 + 154)cm =154 ( 5 + 1) cm 2 Surface area of the cube = 6 × (14)2 = 6 × 196 = 1176 cm2 So, surface area of the remaining solid left out after the cone is carved out ( 2 ) = 1176 –154 + 154 5 cm = (1022 + 154 5 ) cm2.