4/5 is the right answer.....
Base on the visibility formula v = 1.225√a, the altitude at which Dereck is hang gliding is 7.4 miles
<h3>How to find altitude using visibility formula?</h3>
The visibility formula is given as follows:
v = 1.225√a
where
- a = altitude
- v = visibility
Therefore,
v = 67.1 miles
v = 1.225√a
67.1 = 1.225√a
divide both sides by 1.225
√a = 67.1 / 1.225
√a = 54.7755102041
square both sides
√a² = √54.7755102041
a = 7.40104789878
a = 7.4 miles
learn more on visibility here: brainly.com/question/16166215
Subtract the 7 from both sides,
you are left with
11=y
Answer:
13
Step-by-step explanation:
there is a rule that says that if you add any 2 sides, it should be more than the third. 9+21 is greater than 13. 21+13 is greater than 9. 13 is the only number which if you add 9 to it it will be greater than 21. 12 will equal 21, but it still wont work.
hope this helps :))