Grade 8 Geometry Flashcards
pyramid
polygon for a base and triangular sides
pyramids are named by their polygon bases
prism
2 parallel polygons for bases and rectangular sides
prisms are named by their polygon bases
cube is a special rectangular prism made of square bases and sides
equilateral triangle
a triangle whose 3 sides are the same length and whose 3 angles are the same measure (60°)
cone
circular base and a curved surface and one vertex (point) (when the curved surface is spread out flat, it is similar to a triangle)
isosceles triangle
a triangle with 2 sides are the same length and 2 angles are the same measure
cylinder
2 parallel circular bases and a curved surface (when the curved surface is spread out flat, it is in the shape of a rectangle)
scalene triangle
a triangle with no sides are the same length and no angles are the same measure
surface area
the total area of all the sides of a 3-D shape
acute angle
an angle less than 90 degrees (90°)
acute triangle
a triangle that has angles less than 90 degrees (90°)
right angle
an angle that is exactly 90 degrees (90°)
right triangle
a triangle with an angle that is exactly 90 degrees (90°)
obtuse angle
an angle more than 90 degrees (90°)
obtuse triangle
a triangle with an angle that is more 90 degrees (90°)
quadrilateral
a figure with 4 sides
rectangle
a quadrilateral with 4 right angles and 2 pairs of parallel sides, opposite sides are the same length
square
a rectangle whose 4 sides are the same length
parallelogram
a quadrilateral with 2 pairs of parallel sides, opposite sides are the same length, two opposite angles are acute and two opposite angles are obtuse
rhombus
a parallelogram whose 4 sides are the same length
kite
a quadrilateral whose adjacent (side by side, sharing an angle) sides are the same length
trapezoid
a quadrilateral with exactly 1 pair of parallel sides
congruent figures
have the same size and shape
similar figures
have the same shape, but are different sizes
polygon
a closed figure formed by 3 or more lines
polygon 3 sides
triangle
polygon 4 sides
quadrilateral
polygon 5 sides
pentagon