Answer:
0 represents ground level.
Step-by-step explanation:
0 on the number line represents ground level. Based on the photo, the 0 is in between the underground and the space above. The answer cannot be one of the negative numbers because those are all shown to be underground in the photo.
Answer:

Step-by-step explanation:

Answer:
square root of 5 squared minus 4 squared
Step-by-step explanation:
a^2 + b^2 = c^2
c^2 - b^2 = a^2
5^2 - 4^2 = a^2
25 - 16 = a^2
9 = a^2
√
√9=a
a=3
or
a= √25-16
a= √9
a=3
Hope this helps!