Pythagoras Theorem: Pythagoras Theorem is named for Pythagoras, known as Pythagoras of Samos, was an ancient Greek mathematician and philosopher. It is a mathematical formular for finding the lengths of a right angle triangle. 

Hypotenuse: The side opposite the right angle in a right angle triangle. It is also the longest side of the right angled triangle.

Square numbers: A square number is the number we get after multiplying an integer by itself.  

Square root: A square root of a number is a value that, when multiplied by itself, gives the square number.

(e.g. : square root of 16 is 4)

Trigonometry: The study of triangles: their angles, lengths and more.

Sin cos tan: is a shortened description of the three trigonometric functions of sine, cosine and tangent. These functions associate the ratio of two sides of a right-angled triangle with an angle.