A chord equal to alpha subtracts the arc 90 °. Find the radius of the circle.

Let’s construct the radii ОА and ОВ.

The arc AB, by condition, is equal to 90, then the central angle AOB = 90, since it rests on this arc. Then triangle AOB is rectangular and isosceles, OA = OB = R.

Then AB ^ 2 = 2 * R ^ 2.

R = AB / √2 = a * √2 / 2 cm.

Answer: The radius of the circle is a * √2 / 2 cm.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.