How to find the diagonal in the rectangle

Rectangle – a flat geometric figure. A rectangle is a quadrilateral whose all the angles are straight. How to find the diagonal of a square if you know the lengths of its sides?

Instruction

1. Divide the rectangle by a diagonal into two equal triangles. In this case, the diagonal will be the hypotenuse of these triangles. And, as we know from the Pythagorean theorem, the hypotenuse squared is equal to the sum of the squares of the legs.
   
   So, for finding the diagonal of a rectangle need:
   
   find the sum of the squares of the sides of the rectangle A2 + b2, where a and b are the lengths of the sides of the rectangle;
   
   extract from the result the square root.
   
   Example:
   
   Determine the length of the diagonal of rectangle with sides 3 and 4, see
   
   Find the sum of the squares of the sides of the rectangle 32 + 42 = 9 + 16 = 25.
   
   Extract from the result the square root of the diagonal length equal to 5 cm.