A: ### Quick Answer

**Two angles that have the sum of 180 degrees are supplementary angles.** Given one supplementary angle A, a person can find the other supplementary angle B by subtracting A from 180 degrees.

If one of the supplementary angles is 40, then the other supplementary angle is 180 – 40, or 140 degrees. When added together, two supplementary angles also form a straight angle; thus, a straight angle is also equal to 180 degrees.

In geometry, there are other different types of angles besides supplementary angles, such as acute and obtuse angles. While an acute angle is less than 90 degrees, an obtuse angle is more than 90 degrees but less than 180 degrees. In the example given above, the 40-degree angle is an acute angle, and the 140-degree angle is an obtuse angle.

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- Q:
## What is a concave polygon?

A:

Full Answer >**According to Math Open Reference, a concave polygon refers to a polygon or a plane figure that has one or more interior angles that measure greater than 180 degrees.**This type of polygon is the opposite of the convex polygon.Filed Under: - Q:
## What are the properties of a rhombus?

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Full Answer >**Some properties of a rhombus are that its four sides are congruent, the opposite angles have equal measurements, the diagonals bisect each other and form 90 degrees at their intersection and the angles on an adjacent side are supplementary.**Supplementary angles are two angles that add up to 180 degrees.Filed Under: - Q:
## What are the 30-60-90 triangle rules?

A:A 30-60-90 triangle has interior angles equal to 30, 60 and 90 degrees. This is always a right triangle with the 90-degree angle located opposite the longest side of the triangle and the 30 degree angle located opposite the smallest side. The sides of a 30-60-90 triangle are always in a 1:root 3:2 ratio with each other, where 2 represents the longest side of the triangle.

Full Answer >Filed Under: - Q:
## Does a triangle have parallel sides ?

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Full Answer >**A triangle can never have any parallel lines because there must be three angles that add up to 180 degrees, which makes it impossible for the three sides to avoid intersecting.**A parallel line can never intersect with another, and triangles must always have intersecting sides.Filed Under: