Published: 4 years ago

Category: CBSE, Education, Maths

Tags: CBSE, ICSE, Learn Maths, Maths, NCERT

Description:

Right Angle Theorem – Theorem on Circles

Right Angle Theorem – Theorem on Circles CBSE Class IX ICSE Class X Theorem 9 – Angle in a Semi Circle is a Right Angle by Ankit Mahajan for SuccessCDs Education Channel.

About this Video:

Given : Circle with Centre O.

AB is diameter

To Prove :ACB = 900

Proof AOB = 1800 (AB is diameter)

ACB = AOB (Theorem 7)

ACB = 1/2 x 1800

1/2 = 900

Hence Proved!

the degree measure of an arc of a circle is twice the angle subtended it at any pointof alternate segment of the circle w.r.t the arc.

i:e arc(AB)= 2<ACB.

ALSO AB=180deg

2<acb=180

<abc=90.