16.
EBC=90 because is a rigth angle
so we just need DBE
we know
![\begin{gathered} \text{ABD}+\text{DBE}=\text{ABE} \\ \text{ABD}+\text{DBE}=90 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/zawne6isup47x91eg6tln7vg59vt1kegyw.png)
because ABE is a rigth angle
and we know the value of ABD, is 30
so we can replace to find DBE
![\begin{gathered} 30+\text{DBE}=90 \\ \text{DBE}=90-30 \\ \text{DBE}=60 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/e0b33xycs1i4tsvwy0g7hegn97wf6jguws.png)
now
![\begin{gathered} \text{DBC}=\text{EBC}+\text{DBE} \\ \text{DBC}=90+60 \\ \text{DBC}=150 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/mjq4y96ksqfod3p26dix7z1wbourwpt8iy.png)
the measure is 150Degrees
17.
use the same method
we know
![ABF=\text{EBF}+\text{ABE}](https://img.qammunity.org/2023/formulas/mathematics/college/o9xlo5ktkjmvjwy43edue31osqqt32u4fm.png)
ABE=90 because is a rigth angle
to calculate EBF:
![\begin{gathered} \text{EBF}=\text{EBC-FBC} \\ \text{EBF}=90-40 \\ \text{EBF}=50 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/ktt3yyomh8de55hhv1ps2s7wm75el0ptaj.png)
we know EBC=90 because is a rigth angle and FBC=40 is on the exercise
we replace EBF on
![\begin{gathered} \text{ABF}=\text{EBF}+\text{ABE} \\ \text{ABF}=50+90 \\ \text{ABF}=140 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/4tjr24uonoore83f7cwatjaixxi7js1m5v.png)
the measure of ABF is 140 degrees