Dn80 pipe 88millimeters is According to the plan All openings must be 40mm larger than the pipe. You know that

128mm

Step-by-step explanation:

Given

Required

Determine the length of the openings of the pipe

To do this, we simply add 40mm to the length of the pipe.

This gives:

Hence, the opening must be 128mm

for finding the midpoint of any given 2 pair of points simply add the respective x coordinates with other x coordinate and the y coordinate with other y coordinate and divide them by 2

in your question it will be :

(3+1)/2 for the x coordinate of mid point i.e 2

[8+(-4)]/2 for the y coordinate of midpoint i.e 2

so coordinates of mid point of points (3,8) and (1,-4) will be (2,2)