Answer:
Step-by-step explanation: 10/2 = 5
20^2= x^2 + 5^2
400=x^2+25
x^2=375
x= 19.4
The last answer is correct
And where is the rest of question?
Answer:
Numbers that aren't: 35 and 43. It can literally be any number.
Perfect cubes: 8,64,125,216. You can find perfect cubes by cubing any number. For example 6^3 (6 to the power of 3) is 216. A perfect cube.
Answer: z = 
Step-by-step explanation:
To find <em>z</em>, you must set up a proportion to solve.
To find the altitude of a special right triangle, the formula is:

You can use <em>5</em> as <em>a</em> and <em>2</em> as <em>b</em> to complete the proportion:

Next, to solve:
<u>Step 1</u>: Cross-multiply.

(5)*(2) = z*z
10 = z²
<u>Step 2</u>: Take square root.
10 = z²
√10 = z
I hope this helps!