Question

A, B, C are any points on the circle with centre O. m(arc BC)=140${}^{\circ }$ and m(arc AB)=100${}^{\circ }$. Then m(arc ABC) = .

• A. 40${}^{\circ }$
• B. 260${}^{\circ }$
• C. 220${}^{\circ }$
• D. 240${}^{\circ }$

Answer 1

The correct option is D 240${}^{\circ }$

By property of sum of measure of arcs, we must have
m(arc ABC) = m(arc AB) + m(arc BC)
$⟹$ m(arc ABC) = 100${}^{\circ }$ + 140${}^{\circ }$
= 240${}^{\circ }$