Your sister says the horizontal measure from her to the rock wall is 5.5 feet, while the horizontal distance is 13.42 feet. what is the approximate height of her rock wall to the nearest tenth.

12 feet

Step-by-step explanation:

Given in the question,

horizontal distance from sister to rock wall = 5.5 feet

diagonal distance from sister to rock wall's peak = 13.42 feet

As we know this figure make a right angle triangle, so we will apply pythagorus theorem

hypotenuse² = height² + base²

13.42² = height² + 5.5²

13.42² - 5.5² = height²

149.85 = height²

height  = √149.85

height  = 12.24 feet

Approximate height of her rock wall to the nearest tenth =  12 feet

(a) the volume of the cone is 20/3 in3

hence, option a is correct.