An obtuse angle in math refers to an angle that is greater than 90° but less than 180°. For example, putting together two 45° acute angles can make an obtuse angle. This is a basic concept in learning geometry.

If 'survey' refers to a statistical method (like sampling surveys), then it falls under a specific term in applied statistics.

A 'quadratic graph' usually refers to the graph of a quadratic function, which is shaped like a parabola. This is an important topic in middle school math and is mainly used to describe the curved relationship between variables.

A line of symmetry refers to a line along which a shape or the graph of a function can be folded so that both sides match perfectly. It’s widely used in math geometry, function analysis, and chemical crystal structures, and the way you determine it and the number of symmetry lines can vary depending on the context.

The angles in a polygon mainly include two key concepts: interior angles and exterior angles.

A polyhedron usually refers to a solid figure in math that's made up of polygons.

"Quantitative" in math refers to quantities that can be assigned numerical values and measured; they can be expressed with specific numbers (with or without units) and used in mathematical operations.

Symmetry order (also called symmetry number) refers to the minimum number of times an object or system coincides with itself under operations like rotation, translation, or interval changes. It's usually denoted as n, corresponding to n-fold symmetry.

Qualitative data in math and statistics refers to non-numerical data that can't be used for arithmetic operations and is only meant to represent categories, attributes, or characteristics.

Binary is a method of counting using just the digits 0 and 1, with the rule of carrying over when reaching two. Computers basically operate using this system.