A right-angled triangle (also called a right triangle) is a triangle with a right angle (90°) as one of its angles.
The side opposite the right angle ( 90 ° ) is called the hypotenuse. It is always the longest side
Sometimes a triangle can have two names to describe it, e.g. it can be a right-angled triangle and also isosceles.
By the end of this section you should be able to: ● identify and construct right angled triangles
c a b a a b b a b
Construct a right-angled triangle, given the length of the hypotenuse and one other side
C 1
Draw a rough sketch of the triangle to be constructed. Include the given information in your sketch.
A 3
With the centre of the protractor on the point A and in line with [AB] , measure an angle of 90°. Mark the point X as shown. Draw a ray from A through X.
B 4 2
Draw a line segment [AB] , which has a length equal to the side given that is not the hypotenuse.
A B 13
c
With the compass point onB and compass width equal to the length of the given hypotenuse, draw an arc on the ray [AX . Label the intersection of the arc C.