Question

If the radius of a circle is 30cm find the length of a chord which is 10cm from the centre

Answer 1

Answer:

40√2 or 56.7cm

Step-by-step explanation:

radius of circle, r  = 30cm

distance of chord from centre to radius, d = 10cm

let the length of chord be 2l

we can consider r,d and l as sides of a right angled triangle with r as hypotenuse, l as base and d as altitude

we know, base² = hypotenuse²-altitude²

                     l² = [r²-d²]

                        = 30²-10²

                        = 900-100

                        = 800

                     l  = √800

                        = 20√2

thus , length of chord 2l = 2x20√2

                                     = 40√2cm = 56.7cm