Answer:
The sum of all exterior angles of BEGC is equal to 360° ⇒ answer F only
Explanation:
* Lets revise some facts about the quadrilateral
- Quadrilateral is a polygon of 4 sides
- The sum of measures of the interior angles of any quadrilateral is 360°
- The sum of measures of the exterior angles of any quadrilateral is 360°
* Lets solve the problem
- DEGC is a quadrilateral
∵ m∠BEG = (19x + 3)°
∵ m∠EGC = (m∠GCB + 4x)°
∵ The sum of the measures of its interior angles is 360°
∴ m∠BEG + m∠EGC + m∠GCB + m∠CBE = 360
∴ (19x + 3) + (m∠GCB + 4x) + m∠GCB + m∠CBE = 360 ⇒ add the like terms
∴ (19x + 4x) + (m∠GCB + m∠GCB) + m∠CBE + 3 = 360 ⇒ -3 from both sides
∴ 23x + 2m∠GCB + m∠CBE = 375
∵ The sum of measures of the exterior angles of any quadrilateral is 360°
∴ The statement in answer F is only true