Question

The lenghth of common chord of two intersecting circles 30 cm if the radii of two circle is 25 cm and 17 cm find distance between centre

Answer 1

Draw the intersecting circles and common chord. Draw line from center of the circle to point of intersection of circles and perpendicular line from center to common chord. This gives right angle triangle on each circle.
Distance between centers =
$\sqrt{ {25}^{2} - {15}^{2} } + \sqrt{ {17}^{2} - {15}^{2} } = 28$
Note: 15 is half of the length of common chord