12
Question Now mark any four points on your paper so that no three of them are on one line. Label them A, B, C, and D. Draw all possible lines going through pairs of these points. How many lines do you get? Name them. How many angles can you name using A, B, C, and D? Write them all down and mark each of them with a curve as in Fig. 2.9.
Number of lines = 6; \(\overleftrightarrow{AB}\), \(\overleftrightarrow{BC}\), \(\overleftrightarrow{CD}\), \(\overleftrightarrow{AD}\), \(\overleftrightarrow{AC}\) and \(\overleftrightarrow{BD}\)
The number of angles (including A, B, C, and D) = 12; ∠ABC, ∠ABD, ∠DBC, ∠BCD, ∠BCA, ∠ACD, ∠CDA, ∠CDB, ∠BDA, ∠DAB, ∠DAC, and ∠BAC.
2.6 Comparing Angles Figure it Out (Page No. 23)