Given: Circle O with diameter LN and inscribed angle LMN
Prove: is a right angle.

What is the missing reason in step 5?

Statements

Reasons
1.
circle O has diameter LN and inscribed angle LMN
1.
given
2.
is a semicircle
2.
diameter divides into 2 semicircles
3.
circle O measures 360o
3.
measure of a circle is 360o
4.
m = 180o
4.
definition of semicircle
5.
m∠LMN = 90o
5.
?
6.
∠LMN is a right angle
6.
definition of right angle
HL theorem
inscribed angle theorem
diagonals of a rhombus are perpendicular.
formed by a tangent and a chord is half the measure of the intercepted arc.