Angles And Arcs In Circles-Central And Inscribed

                     Lesson 1

Problem:  

SD is diameter,

< DLA=x+5,

< ALS=2x+7,

< SLB=52°,

Find x

Solution    Sum of all the angles inscribed in the circle = 180°

Step 1:  < DLA + < ALS + < SLB + < DLB = 180°

Solution    Since SD is diameter, < DLA + < ALS = 90°

Step 2: (x+5) + (2x+7) = 90°

3x+12 = 90°

Solution x=78°/3; x=78

Step 3:

Solution    Answer: 78

Step 4:          

                                                            Complete      

                                                           Try two practice problems:  

Do the following:

A.

MB is diameter, < MBV=45°, find y

B.

Minor arc AV=44°, find c.

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