Answer: MH = 7
=====================================================
Step-by-step explanation:
The double tickmarks for quadrilateral MATH show that MA = TH. Since TH is 5 units long, this makes MA the same length as well.
For quadrilateral ROKS, we have RO = 15. For "MATH" and "ROKS" we have "MA" and "RO" as the first two letters of each four-letter sequence; meaning that MA and RO correspond together.
The ratio of the corresponding segments is RO/MA = 15/5 = 3.
The larger quadrilateral has each side length 3 times longer than the smaller quadrilateral's corresponding side lengths.
--------------
In short,
larger side = 3*(smaller side)
--------------
Using this scale factor of 3, we can find MH
larger side = 3*(smaller side)
RS = 3*(MH)
21 = 3*MH
3*MH = 21
MH = 21/3
MH = 7