if m∠acd = 40°, then m∠dcb = ?°
if m∠acd = 40°, then m∠dcb = ?°
Answer
Answer:
$140$
Explanation:
Step1: Identify angle - relationship
$\angle ACD$ and $\angle DCB$ are supplementary.
Step2: Use supplementary - angle formula
$m\angle ACD + m\angle DCB=180^{\circ}$
Step3: Solve for $m\angle DCB$
$m\angle DCB = 180^{\circ}-m\angle ACD$ Substitute $m\angle ACD = 40^{\circ}$ into the formula: $m\angle DCB=180 - 40=140^{\circ}$