How do you find #abs( -2+i )#? Precalculus Complex Numbers in Trigonometric Form Complex Number Plane 1 Answer sente May 3, 2016 #|-2+i| = sqrt(5)# Explanation: Given a complex number #a+bi#, that number's modulus, denoted #|a+bi|#, is given by #|a+bi| = sqrt(a^2+b^2)# In this case, that gives us #|-2+i| = sqrt((-2)^2+1^2) = sqrt(4+1) = sqrt(5)# Answer link Related questions What is the complex number plane? Which vectors define the complex number plane? What is the modulus of a complex number? How do I graph the complex number #3+4i# in the complex plane? How do I graph the complex number #2-3i# in the complex plane? How do I graph the complex number #-4+2i# in the complex plane? How do I graph the number 3 in the complex number plane? How do I graph the number #4i# in the complex number plane? How do I use graphing in the complex plane to add #2+4i# and #5+3i#? How do I use graphing in the complex plane to subtract #3+4i# from #-2+2i#? See all questions in Complex Number Plane Impact of this question 1142 views around the world You can reuse this answer Creative Commons License