Hello,

I'd be very grateful if anyone could help me.

I'm a student, studying foundation Biology alone by distance learning. I've just started learning the very basics of microscopy. I've so far learned the equation required to calculate the "magnification" of an object: ("magnification = image size/object size"). I've also learned the equations for calculating the "size of an object" when given the "size of an image" and the "magnification of an object" ("size of object = size of image/magnification") and the "size of an image" when given the "size of an object" and "magnification" ("size of image = size of object x magnification").

The book I'm studying from has an exercise on magnification, where I must answer a number of questions. Each question must initially be interpreted, and then the answer calculated using one of the above equations (whichever one I think is appropriate).

I've been able to answer several of them without any problems, however one of them has confused me.

This is:

"A publisher wants to put a photograph of a weightlifter in her book. The athlete is 1.85 m tall. The photograph needs to be shrunk 50 times. What is the height of the weightlifter in the photograph?"

How would I interpret this question and what steps would I take to calculate the answer? Which of the 3 equations would I use ("magnification = image size/object size", "object size = image size/magnification" or "image size = object size x magnification")? My initial thought was that I should be calculating "image size" and using that equation, as my interpretation of the question was that the "1.85 m" value was the object size and the "50" value was something to do with the magnification. I, hence, thought that a value for image size needed to be found.

However, doing the equation "image size = object size x magnification" ("image size = 1.85 m x 50") didn't get me anything like the correct answer (I have a copy of all the answers to the questions in the back of my exercise book, albeit without any helpful explanations on the correct way to calculate them). I have obviously made a big mistake, which I'm sure has a lot to do with how I interpreted the question in the first place.

I wonder whether I am perhaps correct to use the equation "image size = object size x magnification" but MUST FIRST do something else with the "1.85" and "50" values (work out something else/do another calculation first). The 3 equations are the only material I've been given to help me answer this question. I'm unsure what to do with them.

Could anybody please help me out by talking me though how I should have initially interpreted the question and then give me a step-by-step in working it out? What calculations must be made?

The answer to the question at the back of my exercise book is: 37 mm. How do I calculate and get to this?

I'm also aware that these equations require you to convert all the values into the same units using standard form. Must I do anything like that here?

I would be incredibly appreciative if anyone can help. I know this is very basic stuff for the forum, which I know is generally focused on much more in depth Biology. It's just really worrying me that I can't work out this question. I very much want to grasp this so that I can answer other similar questions with ease in the future (especially in exams). I have dyscalculia (a sort of math dyslexia) which seriously impedes me from grasping simple mathematical concepts and answering questions. This is the reason, I believe, I am struggling so much with this question! I'm a self-study student, so I don't have anyone to turn to for help with this microscope topic!

Thank you very much for your time and help.