4.5. because ⁼3=9, and 9 divided by 2 is 4.5
The best way to estimate it is to do "written addition" in your head, adding 1+8, then 9+3, all the way until you get to the front. the actual answer is 189,459, so your answer should be somewhere close to that.
If c is the hypotenuse and b is the leg, then the third side (a):

If b and с are legs, then hypotenuse (a):
Answer:
Step-by-step explanation:
An unknown number minus 8.