Measuring Space: Perimeter and Area

4. The region of a circle bounded by an arc and the two radii containing its endpoints
6. The constant Greek symbol used to denote the ratio of a circle’s circumference to its diameter
10. The portion of a circular region bounded by an arc and the chord joining its endpoints
11. The scholar of Sangamagrama who discovered the first exact infinite series formula for π
13. The mathematician who "trapped" the value of π between 96-sided inscribed and circumscribed polygons
16. The mathematician of Alexandria who developed a formula for triangle area using only the lengths of its three sides
17. A property of a 4-gon whose vertices all lie on a circle, making it compatible with Brahmagupta’s area formula
18. An important part of mathematics where a broad result (like Brahmagupta's formula) includes a "special case" (like Heron's formula)
19. A category of numbers, including π, that cannot be written as a ratio of two integers
20. A line segment joining a triangle's vertex to the midpoint of the opposite side, dividing it into two equal areas

1. The geometric term for the angle formed at the center of a circle by an arc
2. The ancient civilization (c. 1900 BCE) that calculated a π value of 3.125 by comparing a circle to a hexagon
3. A connected portion of a circle's edge defined by two endpoints
5. The specific name used for the perimeter of a circle
7. The distance between the starting points of adjacent lanes on an athletics track to ensure everyone runs the same distance
8. The Sanskrit term meaning "approaching" used by Āryabhaṭa to indicate that his value for π was an approximation
9. The area of mathematics birthed by Mādhava’s shift from geometric cutting to the analytical summing of numbers
12. The ancient mathematician whose Śhulbasūtra described a geometric method to "square a rectangle"
14. The total length around the border of any given shape
15. Denoted as 's', this is the value representing half of a triangle's or quadrilateral's total perimeter