Answer:
a. [tex] x = \boxed{\, 75 \, }^\circ [/tex]
b. Because [tex]\angle ABC \textsf{ and } \angle EFG[/tex] are co-exterior angles and they are supplementary.
Step-by-step explanation:
To solve the size of angle [tex] x [/tex], we'll need to use the concept of co-exterior angles.
a) To find the size of angle [tex] x [/tex], we'll start by recognizing that the sum of co-exterior angles is 180°.
Given:
[tex]\angle EFG = 105^\circ[/tex] (co-exterior angle to angle [tex] x [/tex])
b) Now, we can set up an equation to find angle [tex] x [/tex]:
[tex]\begin{aligned} \sf \angle EFG + \angle ABC &= 180^\circ \quad \textsf{(Sum of angles of a co-exterior angle are supplementary)} \\\\ 105^\circ + x &= 180^\circ \\\\ x &= 180^\circ - 105^\circ \\\\ x &= 75^\circ\end{aligned}[/tex]
a) Therefore, the size of angle [tex] x [/tex], or [tex] \angle ABC [/tex] is [tex] 75^\circ [/tex].
b) Reasons:
[tex] \angle ABC = 75^\circ [/tex] because [tex]\angle ABC \textsf{ and } \angle EFG[/tex] are co exterior angles and they are supplementary.