1.
The set of all points in a plane that are the same distance from a given point, called the center.
Correct Answer
A. Circle
Explanation
A circle is defined as the set of all points in a plane that are equidistant from a given point called the center. This means that any point on the circle is the same distance away from the center. Therefore, the correct answer is circle.
2.
A segment that passes through the center of a circle and has both endpoints on the circle.
Correct Answer
C. Diameter
Explanation
A diameter is a segment that passes through the center of a circle and has both endpoints on the circle. It is the longest chord in a circle and divides the circle into two equal halves. The radius, on the other hand, is a segment that connects the center of the circle to any point on the circumference. Length and width are not specific to circles and do not have the same definition as diameter.
3.
A segment that has one endpoint at the center and the other endpoint on the circle.
Correct Answer
D. Radius
Explanation
A radius is a segment that has one endpoint at the center of a circle and the other endpoint on the circle itself. It represents the distance from the center of the circle to any point on the circle's circumference.
4.
What is 3.14 or 22/7 called?
Correct Answer
B. Pi
Explanation
Pi (π) is a mathematical constant that represents the ratio of a circle's circumference to its diameter. It is an irrational number, meaning it cannot be exactly expressed as a simple fraction, but 22/7 is a common approximation. The decimal representation of π is approximately 3.14159, and it continues infinitely without repeating.
5.
The space inside of a 2D shape.
Correct Answer
B. Area
Explanation
The area of a 2D shape refers to the space enclosed by the shape. It is a measure of the surface covered by the shape and is typically expressed in square units. The area can be calculated by multiplying the length and width of the shape for regular shapes like rectangles and squares, or by using specific formulas for irregular shapes like triangles and circles. The concept of area is important in various fields such as geometry, architecture, and physics, as it helps determine the amount of material needed or the amount of space occupied by an object.
6.
The distance around a circle.
Correct Answer
B. Circumference
Explanation
The term "circumference" refers to the distance around a circle. It is the measurement of the outer boundary of a circle. This term is specifically used to describe the length of the boundary of a circle and is different from other measurements like area or volume, which are used to describe the space inside or occupied by the circle. Therefore, "circumference" is the correct answer in this case.
7.
"Closed" 2-dimensional shapes made up of 8 straight lines.
Correct Answer
D. Octagon
Explanation
An octagon is a polygon with eight sides and eight angles. It is a closed two-dimensional shape, meaning all its sides are connected, forming a boundary that encloses an area. The most well-known type of octagon is the regular octagon, where all sides and angles are equal. Each internal angle of a regular octagon measures 135 degrees, and the sum of all internal angles is 1080 degrees. Octagons can be found in various applications, such as architecture (e.g., stop signs) and design. The name "octagon" comes from the Greek words "okto," meaning eight, and "gonia," meaning angle.
8.
"Closed" 2-dimensional shapes made up of 6 straight lines with all sides and angles of equal measure.
Correct Answer
C. Regular Hexagon
Explanation
A regular hexagon is a polygon with six equal sides and six equal angles. Each internal angle of a regular hexagon is 120 degrees, and the sum of all internal angles is 720 degrees. A regular hexagon has rotational symmetry and six lines of reflectional symmetry. It is a common shape in nature and man-made structures, often seen in honeycombs and tiling patterns. The name "hexagon" comes from the Greek words "hex," meaning six, and "gonia," meaning angle.
9.
Closed 2-dimensional shapes made up of 8 straight lines with opposite sides equal and angles of 135 degrees.
Correct Answer
B. Regular Octagon
Explanation
A regular octagon is a closed 2-dimensional shape with eight straight sides of equal length and eight equal angles of 135 degrees each. The term octagon can refer to any eight-sided polygon, but a regular octagon specifically has all sides and angles equal.
10.
Closed 2-dimensional shapes made up of 5 straight lines with all sides and angles of equal measure.
Correct Answer
D. Regular Pentagon
Explanation
A regular pentagon is a closed 2-dimensional shape with five straight sides of equal length and five equal angles of 108 degrees each. A pentagon in general does not necessarily have equal sides and angles unless specified as regular.