In order to get the measure of the angle ∠EOD you first determine the angles ∠DOB and ∠EOB.
By the measure that appears in the image you have:
∠DOB = 65
∠EOB = 40
The angle ∠EOD is the difference between the previous angles, just as follow:
∠EOD = ∠DOB - ∠EOB = 65 - 40 = 15
Hence, angle ∠EOD is 15°