Answer:
36x
Step-by-step explanation:
OF= 6x (given radius of circle)
OB=OF+FB
= 6x +6x(given OF=FB)
= 12x
Angle D= angle B and angle O= 60°( given arc EF is 60°)
D + B + O= 180° ( sum of angles in a triangle)
x + x + 60= 180° ( let the value of remaining angles be x and D= B)
2x= 180 -60
x = 120/2
x= 60°
now, triangle DOB is a equilateral triangle because all angles are equal.
so, OB=DB=OD= 12x ( all sides are equal in equilateral triangle)
so,
perimeter of DOB= OB+DB+OD
= 12x+12x+12x
= 36x
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