A chord is 2cm from the centre of a circle. If the radius of the circle is 5cm, find the length of the chord

To solve this problem, we can use the Pythagorean theorem to find the length of the chord. We know that the radius of the circle is 5cm and the distance from the centre of the circle to the chord is 2cm. We can draw a perpendicular line from the centre of the circle to the chord, which will divide the chord into two equal parts. This perpendicular line will also bisect the chord and form a right triangle with the radius of the circle and half of the chord. The hypotenuse of this triangle is the radius of the circle, which is 5cm, and one leg is half of the chord, which we can call x. The other leg is the distance from the centre of the circle to the chord, which is 2cm. Using the Pythagorean theorem, we can solve for x: 5^2 = x^2 + 2^2 25 = x^2 + 4 x^2 = 21 x = √21 Therefore, the length of the chord is twice the value of x, which is 2√21cm. Hence, the correct answer is option A.