Geometry & Figures

Problem

Per-cell counts give the front and side views

The top and front views of a ten-cube stack are given. We need the view from the side.
top front side front side
Geometry
Your answer
How to solve
Strategy Organize Information in More Ways — The front view caps each column but does not fill it in, so some stacks are still unknown. The total of ten is the extra fact that closes the gap -- once every height is known, the side view reads straight off.
1STEP 1

Fill in the column that the front view settles

Column 1 is only 1 high from the front, so none of its three stacks can be taller than one -- all three are exactly 1.

1 + 1 + 1 = 3
2STEP 2

Fill in the column with a single stack

Column 2 has only one occupied cell, so the front view's 3 must be that stack's height.

3STEP 3

Use the total for the last column

Column 3 has two stacks, neither taller than 2, and they must make up what is left of the ten.

10 - 3 - 3 = 4, 4 - 2 = 2
4STEP 4

Read the side view along the rows

From the right the front row appears leftmost, and each row shows only its tallest stack.

1 + 0 = 1, 3 + 0 = 3, 2 + 0 = 2
Answer
Columns 1, 3 and 2 cells high, front to back
Add the heights: 1 and 2 in row 1, 1, 3 and 2 in row 2, 1 in row 3 -- ten cubes, and the front view still reads 1, 3, 2.
Takeaway

A view caps each line but does not fill it in -- the total number of cubes is what settles the rest.

  • Fill in the column that the front view settles
  • Fill in the column with a single stack
  • Use the total for the last column
  • Read the side view along the rows

▶ Practice — 12 problems