Answer :
Option A) 84°
Step-by-step explanation:
Its an equilateral triangle ( since DE and EF = 5)
So they have the same angles as well ..
which means angle D = 48° and angle F = 48°
angle D + angle F + angle E = 180° (angle sum property)
48° + 48° + angle F = 180°
96° + angle F = 180°
angle F = 180° - 96°
= 84°
