Answer:
By the Pythagorean Theorem
[tex]DB=\sqrt{AD^2+AB^2}=\sqrt{8.9^2+17.6^2 } =19.72232[/tex]
In the figure triangles ABD(red) and ADE(green) are similars because:
AED=DAB=90
ADE common angle
Then [tex]\frac{AD}{BD}= \frac{AE}{AB}=\frac{DE}{AD}[/tex]
[tex]b=AE=\frac{AD\times AB}{BD}= \frac{8.9\times 17.6}{19.72}=7.94227[/tex]
