PDF chapter test TRY NOW

Answer variants:
\(\frac{BO}{DO}\)
\(\frac{AO}{BO}\)
\(\angle OBA\)
\(\frac{AO}{BO} = \frac{CO}{DO}\)
\(\angle AOB \sim \triangle COD\)
\(AB\) is parallel to \(CD\)
[Since corresponding sides of similar triangles]
\(\angle OAB\)
[Since they are alternate angles]
\(ABCD\) is a trapezium. Here, the sides \(AB\) and \(CD\) are parallel to each other. Also, the diagonals intersect at \(O\). Prove that \(\frac{AO}{BO} = \frac{CO}{DO}\).
 
Let us look at the figure given below for a better understanding.
 
21 Ресурс 1.svg
 
We already know that in \(\triangle ABC\) and \(\triangle COD\), 
 . [Given]
 
This makes,
 \(=\) \(\angle DCO\), and 
 \(=\) \(\angle ODC\).
 
  
By  similarity criterion, we have, "If two angles of one triangle are respectively equal to two angles of another triangle, then the two triangles are similar."
 
Thus,
.
 
Also, \(\frac{AO}{CO}\) \(=\)
 which can also be written as 
 \(=\) \(\frac{CO}{DO}\).
 
 
Hence, the required condition 
 is proved.