Help! I have to teach a 'struggling student' how to solve a Geometry question as part of a job interview. The interview is for a general teacher's aide position. The employer understands that I am certified to teach English and cannot be relied upon to teach Math to anyone's child. They just want to assess my basic teaching skills.
Here's the question:
A 15-ft ladder is leaning against a 30-ft wall. The bottom end of the ladder is 9 ft from the wall. How many feet above the ground does the ladder touch the wall?
I think the answer is 12. (I drew a picture, using a ruler). Is that the correct answer? And how can I use math language to explain how to solve the problem? A picture will not be enough. Would anyone be willing to assist a struggling job seeker?