1.
A set of rules related to the mathematical principles of paper folding is the?
Correct Answer
C. Huzitaâ€“Hatori axioms
Explanation
The Huzita-Hatori axioms are a set of rules related to the mathematical principles of paper folding. These axioms were developed by mathematicians Masahiko Huzita and Jun-ichi Hatori in the 1990s. They describe the seven fundamental operations that can be performed with a straightedge and compass on a piece of paper. These operations include folding a line in half, bisecting an angle, and constructing parallel lines. The Huzita-Hatori axioms are used in origami mathematics and have applications in geometry and robotics.
2.
Maekawa's theorem states that at any vertex the number of valley and mountain folds always differ by?
Correct Answer
B. Two
Explanation
Maekawa's theorem states that at any vertex, the number of valley and mountain folds always differ by two. This means that if there are x valley folds at a vertex, there will be x+2 mountain folds. This theorem is important in origami and paper folding as it helps ensure that the folds are balanced and allows for the creation of more complex and intricate designs.
3.
Kawasaki's theorem states that at any vertex, the sum of all the odd angles adds up to?
Correct Answer
D. 180 degrees
Explanation
Kawasaki's theorem states that at any vertex, the sum of all the odd angles adds up to 180 degrees. This means that if we have a polygon with multiple vertices, and we sum up all the odd angles at each vertex, the total will always be 180 degrees. This theorem is a useful tool in geometry to calculate the sum of angles in polygons.
4.
In the flat folding of a pure origami, a sheet can never penetrate a?
Correct Answer
A. Fold
Explanation
In the flat folding of a pure origami, a sheet can never penetrate a fold. This is because a fold in origami refers to the act of bending the paper along a specific line, creating a crease. The fold acts as a barrier, preventing the sheet from going through it. Therefore, a sheet of paper cannot penetrate a fold in origami.
5.
The product of principal curvatures of a surface at a point is referred to as?
Correct Answer
D. Gaussian curvature
Explanation
The product of principal curvatures of a surface at a point is referred to as Gaussian curvature. Gaussian curvature is a measure of how the surface curves at a particular point. It is named after Carl Friedrich Gauss, who introduced the concept. The Gaussian curvature can be positive, negative, or zero, indicating different types of curvature at the point. A positive Gaussian curvature indicates a surface that curves outward like a sphere, a negative Gaussian curvature indicates a surface that curves inward like a saddle, and a zero Gaussian curvature indicates a surface that is flat.
6.
What is a function that is its own inverse?
Correct Answer
C. Involution
Explanation
An involution is a function that when applied twice returns the original input. In other words, if you apply the function to a value and then apply it again to the result, you will get back the original value. This property makes an involution its own inverse. Therefore, an involution is the correct answer to the question.
7.
Which is not an example of impossible construction of geometric figures?
Correct Answer
B. Heptadecagon
Explanation
A heptadecagon is a polygon with 17 sides, and it is possible to construct it geometrically. Squaring the circle, doubling the cube, and angle trisection, on the other hand, are examples of geometric constructions that have been proven to be impossible using only a compass and straightedge.
8.
A rigid fold that has been used to deploy large solar panel arrays for space satellites is the?
Correct Answer
C. Miura map fold
Explanation
The Miura map fold is a type of rigid fold that is commonly used to deploy large solar panel arrays for space satellites. This fold allows for compact storage and easy deployment, making it ideal for space applications. It is often used because it can be easily unfolded and locked into place, providing a stable and rigid structure for the solar panels to capture sunlight efficiently.
9.
The problem of whether a square or rectangle of paper can be folded so the perimeter of the flat figure is greater than that of the original square is the?
Correct Answer
A. Napkin folding problem
Explanation
The napkin folding problem refers to the challenge of folding a square or rectangle of paper in such a way that the perimeter of the resulting flat figure is greater than that of the original square. This problem is often encountered in the context of decorative napkin folding, where individuals try to create intricate and visually appealing shapes out of napkins. By exploring different folding techniques, one can potentially achieve a higher perimeter for the folded figure, making it a solution to the napkin folding problem.
10.
Which origami folding allows for a greater range of shapes?
Correct Answer
A. Wet
Explanation
Wet origami folding allows for a greater range of shapes because when the paper is wet, it becomes more pliable and easier to manipulate. This allows for more intricate and complex folds to be made, resulting in a wider variety of shapes that can be created.