Answer:
m∠C = 102°
Step-by-step explanation:
The above diagram is a cyclic quadrilateral
Step 1
First we find m∠B
The sum of opposite angles in a cyclic quadrilateral is equal to 180°
m∠D + m∠B = 180°
m∠B = 180° - m∠D
m∠B = 180° - 80°
m∠B = 100°
Step 2
Since we have found m∠B
We can proceed to find the Angle outside to circle
m∠CDA = 2 × m∠B
m∠CDA = 2 × 100°
m∠CDA = 200°
m∠CDA = m∠CD + m∠DA
m∠DA = m∠CDA - m∠CD
m∠DA = 200° - 116°
m∠DA = 84°
Step 3
Find m∠DAB
m∠DAB = m∠DA + m∠AB
m∠DAB = 84° + 120°
m∠DAB = 204°
Step 4
Find m∠C
It you look at the cyclic quadrilateral properly,
m∠DAB is Opposite m∠C
Hence
m∠C = 1/2 × m∠DAB
m∠C = 1/2 × 204
m∠C = 102°
Therefore ,m∠C = 102°
