A solid has plan shown as a 3 by 4 grid (3 rows front to back, 4 columns left to right). The front elevation (viewed from the front, across the 3-row depth) shows heights (left to right) 2, 3, 2, 1. The right-side elevation (viewed from the right, across the 4-column width) shows three columns of heights (front to back) 3, 2, 1. Using these elevations, determine the height of each cell in the plan (a 3 by 4 matrix), then calculate (a) the total number of unit cubes used, and (b) the total external surface area including base, in cm2. Show your working.
(a)Determine the height of each of the 12 plan cells and give the total number of unit cubes used.(3)
(b)Calculate the total external surface area of the solid, including the base, in cm2. Show working.(3)
(Total for Question 5 is 6 marks)