http://www.ck12.org Chapter 9. Circles
TABLE9.1:(continued)
Statement Reason
7.DB∼=DB- 4 ABD∼= 4 CBD
9.AB∼=CB
12. From the above proof, we can also conclude (fill in the blanks):
a.ABCDis a __ (type of quadrilateral).
b. The line that connects the and the external pointB_____^6 ADCand^6 ABC.
13. PointsA,B,C, andDare all points of tangency for the three tangent circles.ExplainwhyAT∼=BT∼=CT∼=DT.
14. Circles tangent atTare centered atMandN.STis tangent to both circles atT. Find the radius of the smaller
circle ifSN⊥SM,SM= 22 ,T N=25 andm^6 SNT= 40 ◦.
15. Four circles are arranged inside an equilateral triangle as shown. If the triangle has sides equal to 16 cm, what
is the radius of the bigger circle?
16. Circles centered atAandBare tangent atW. Explain whyA,BandWare collinear.