Question

What is the measure of DE?

Answer 1

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.

Answer 2

68. Here's how I did it, since there's 360° in a circle, and CE is through the center