91Ó°ÊÓ

As the measurement of angle CBF is already given and the perpendicular relationship between the given lines represents that the measurement of $∠ABE$,$∠CBE$ and$∠DBF$ is equal to 90°.

According to the figure $∠EBF$and $∠CBF$makes the right $∠EBC$so by using this determines the value of $∠EBF$.

$$\begin{gathered} ∠EBC=∠EBF+∠CBF \\ 90=∠EBF+x \\ ∠EBF=90-x \end{gathered}$$

According to the figure$∠EBF$ and$∠DBE$ makes the right$∠DBF$so by using this determines the value of $∠DBE$.

$$\begin{gathered} ∠DBF=∠EBF+∠DBE \\ 90=90-x+∠DBE \\ ∠DBE=90-90+x \\ ∠DBE=x \end{gathered}$$

According to the figure$∠DBA$ and$∠DBE$ makes the right$∠ABE$so by using this determines the value of $∠DBA$.

$$\begin{gathered} ∠ABE=∠DBA+∠DBE \\ 90=∠DBA+x \\ ∠DBA=90-x \end{gathered}$$

According to the figure the right$∠DBF$ and$∠CBF$ makes$∠DBC$so by using this determines the value of $∠DBC$.

$$\begin{gathered} ∠DBC=∠DBF+∠CBF \\ =90+x \end{gathered}$$

Make the complete table by writing the value of obtained angles into their respective columns.