help me pls i did the first question but im confused with the rest id u could answer the rest for me that would be nice of you

Answer:
a. the enclosing boundary of a curved geometric figure, especially a circle.
b. The diameter is the length of the line through the center that touches two points on the edge of the circle.
c. a straight line from the center to the circumference of a circle or sphere
2. a.w b.z c.t d.x
Step-by-step explanation:
that's all i could do pls give brainliest