Question

AB is diameter whose center is O of a circle. If AC is 3 cm and BC is 4 cm, then find AB?

Answer 1

`AB=5`

Explanation:

I have to assume point `C` is on the circle too.

In geometry, if `A,B and C` are points on a circle when the line `AB` is a diameter of the circle, then `angleACB` is a right angle.

Given `AB` is a diameter, and `AC=3, and BC=4`,
`=> angleACB=90^@`
by Pythagorean theorem,
`AB^2=AC^2+BC^2`
`=> AB^2=3^2+4^2=25`
`=> AB=sqrt25=5`