Lee Zhi Xian's answer to Alvin tan's Mathematics College United Kingdom question.

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Lee Zhi Xian
Lee Zhi Xian's answer
51 answers (Tutor Details)
Use the ratio theorem to find OM and ON first. Then find the modulus of MN to get it's length