A picture of the triangle A B C, where A B C is a right-angle and B C is the hypotenuse of another triangle B C D  where d lies on A C

In the diagram, \(\widehat{ABC}=\widehat{BDC}=90^\circ\).

  1. Write down an angle equal to \(\widehat{CBD}\).
  2. Given that \(AC=\quantity{10}{cm}\) and \(BC=\quantity{7}{cm}\), use similar triangles to calculate \(CD\).