Show the number √5 on the number line.
Draw a number line as shown in the figure. Let the point O represent 0 and point Q represent 2. Draw a perpendicular QR at Q on the number line such that QR = 1 unit. Join OR. Now, ∆OQR is a right angled triangle.
By Pythagoras theorem, we have
OR2 = OQ2 + QR2
= (2)2 + (1)2
= 4 + 1
∴ OR = √5
Taking O as the centre and radius OR = √5, draw an arc cutting the number line at C.
Clearly, OC = OR = √5
Hence, C represents √5 on the number line.