Question

If a semi circle has a diameter of 4cm then what is the perimeter?

Answer 1

`~~10.283" cm"`

Explanation:

`"perimeter "=1/2pid+4`

`"that is the semi circle plus diameter"`

`"color(white)(xxxxxx)=(1/2xxpixx4)+4`

`color(white)(xxxxxx)=2pi+4~~10.283" cm to 3 dec. places"`

Answer 2

`(4+2pi)"cm"`

Explanation:

`d=4 "cm"` - - - i
`2r=d` - - - ii
`"Perimeter"_"semicircle"= 2r+(2pir)/2`
Substitute in ii,
`rArrd+(dpi)/2`
Substitute in i,
`rArr(4+(4pi)/2)"cm"`
`rArr(4+2pi)"cm"`