Question

Given the triangle points `(x,y)->(3,8) and (3,1) and (6,1)` what is the length of the perimeter?

Answer 1

Note that the question does not state the level of precision that should be applied to the answer. So I choose:

An approximation of the total length is `7+3+7.6=18.6`

Explanation:

A to C `-> y_a - y_c = 8-1=7`
C to B `-> x_b - x_c= 6-3=3`

A to B we use Pythagoras `(AB)^2=(AC)^2+(BC)^2`

`=> AB=sqrt(7^2+3^2)=sqrt(49+9)=sqrt(58)`

Note that `8xx8=64" and that "7xx7=49`

`sqrt(58) ~~7.6157731..... ~~7.6` to 1 decimal place

Thus an approximation of the total length is `7+3+7.6=18.6`