Question

What is the length of line HI and IJ

Answer 1

HI =
`4√(41)` , IJ =
`4√(41)`

Explanation:

The number of AB spaces is 15, the BC is 20, and the CD is 15. Looking at the given length, you can see that it is twice the number of cells.

If you draw a line perpendicular to the line HG in I, it becomes a right triangle. The lengths of HI and IJ can be calculated using Pythagoras on a right triangle.

Suppose that the vertical line is L.

HL = 10

IL = 8

(HI)² = (HL)²+ (IL)² = 10²+8²=164

HI =
`2\sqrt{41\\` -> (It's twice the number of spaces.) -> HI =
`4√(41)`

IJ can be obtained in the same way.

IJ =
`2\sqrt{41\\` -> (It's twice the number of spaces.) -> IJ =
`4√(41)`

Answer 2

Answer 20mm

Point H is even with point E and I is exactly half way in between E and F. EF = 40 half of that is 20. This also works with HG, BC, and JK.
HI and IJ are the same length so both are 20mm