According to Pythagorean Theorem A? +a? =b? When a= 1 and b= root number two, the known edge data is directly brought into the calculation when doing the problem.
In a right-angled triangle of 30 60 90, let the right-angled side of 30 be A, the hypotenuse be B and the other right-angled side be C.
∵Rt△ The right angle side opposite to the 30 angle is half of the hypotenuse.
∴2a=b
According to Pythagorean Theorem A? +c? =4a? When a= 1, b=2 c= root number three.