Aussie Maths & Science Teachers: Save your time with SmarterEd
Craig has a drum which has the top and bottom in the shape of regular octagons, as shown below.
The other faces are isosceles triangles.
How many edges does Craig's drum have?
`32`
`text(Top and bottom edges)`
`= 8 xx 2 = 16`
`text(Side edges)`
`= 8 xx 2 = 16`
`:.\ text(Total edges )` | `= 16 + 16` |
`= 32` |
The edges of a 4 × 4 × 4 cube are formed using blocks as shown below:
In total, 32 blocks are used.
How many blocks would be needed to make the edges of an 8 × 8 × 8 cube in the same way?
`80`
`text(Cubes in the top level = 28)`
`text(Cubes in the bottom level = 28)`
`text{Cubes in the vertical pillars (not including top/bottom level)}`
`=4 xx 6`
`= 24`
`:.\ text(Total blocks)` | `= 28 + 28 + 24` |
`=80` |