Question

I need help... If meas. of angle DBC=40, then meas. of arc CD and arc BC=? angle meas. of ECB=? DCF=? BDC=? Refer to picture below.

Answer 1

If meas. of angle DBC=40, then meas. of arc CD = 80 because an inscribed angle of a circle has measure half its arc.

and arc BC= 100 because it and arc CD form a semi-circle with measure 180

angle meas. of ECB= 50 because it is an angle formed by a tangent and a secant on the circle and has measure half its intercepted arc.

DCF= 130 because it and forms a linear pair with anglee ECB

BDC= 90 because an angle inscribed in a semi-circle is a right angle.

Answer 2

thank you!!