Answer:
The measure of arc DE is 68°
Option 1 is correct.
Step-by-step explanation:
Given the figure in which EC is diameter as it pass through centre
m(arc DC)=112°
m(arc AB)=72°
∠ECB=51°
we have to find the measure of arc DE i.e m(arc DC)
Let m(arc DE) = ∠DOE = x°
As EC is a straight line
Therefore ∠x and ∠DOC forms a linear pair
⇒ these two angles are supplementary
⇒ x + ∠DOC=180°
x + 112° = 180°
x= 180°-112°=68°
Hence, the measure of arc DE is 68°
Option 1 is correct.
