Answer:

Step-by-step explanation:
The formula is 
<em>We need to solve for
, so we can perform the steps shown below:</em>

Hence, the third answer choice is correct.
The answer is a² + 6. "Sum of a squared and 6" means you square a value and then add 6 to it.
The angle of depression is 29.0521°. So it is a safe landing.
Step-by-step explanation:
Step 1:
The plane is flying at a height of 25,000 feet and 45,000 feet away from the landing strip. Assume it lands with an angle of depression of x°.
So a right-angled triangle can be formed using these measurements. The triangle's opposite side measures 25,000 feet while the adjacent side measures 45,000 feet. The angle of the triangle is x°.
To determine the value of x, we calculate the tan of the given triangle.

Step 2:
The length of the opposite side = 25,000 feet.
The length of the adjacent side = 45,000 feet.

So x = 29.0521°. Since x < 30°, it is a safe landing.