The length of the shorter leg is 9 mm.
The length of the longer leg is 12 mm.
The length of the hypotenuse is 15 mm.
Pythagoras theory applies to every right triangle. If
- The shorter leg = a
- The longer leg = b
- The hypotenuse = c

Explanation:
Known
- Longer leg = shorter leg +3 mm
b = a+3 mm - Hypotenuse = shorter leg +6 mm
c = a+6 mm
Asked
Answer








(a-9) (a+3)=0
a-9=0 or a+3= 0
a=9 or a=-3 (impossible)
Shorter leg
a=9 mm
Longer leg
b = a+3
b = 9+3
b = 12 mm
Hypotenuse
c = a+6
c = 9+6
c = 15 mm