Answer:
The value of x is 14.75 ⇒ (2)
Step-by-step explanation:
- If the vertices of a quadrilateral lie on the circumference of a circle, then this quadrilateral is a cyclic quadrilateral
- In the cyclic quadrilateral, every two opposite angles are supplementary (the sum of their measures is 180°)
In the given figure
∵ The vertices of the quadrilateral BCED lie on the circumference of circle A
→ By using the 1st rule above
∴ BCED is a cyclic quadrilateral
∵ ∠B and ∠E are opposite angles in the cyclic quadrilateral BCED
→ By using the 2nd rule above
∴ m∠B + m ∠E = 180°
∵ m∠B = 6x + 10
∵ m∠E = 81.5°
∴ 6x + 10 + 81.5° = 180°
→ Add the like terms on the left side
∴ 6x + 91.5 = 180
→ Subtract 91.5 from both sides
∵ 6x + 91.5 - 91.5 = 180 - 91.5
∴ 6x = 88.5
→ Divide both sides by 6 to find x
∴ x = 14.75
