Geometry Basics
a closed four-sided shape
polygon
a closed two dimensional shape with 3 straight sides
Triangle
has four equal sides and four equal angles
Square
Can a triangle be constructed?
123 degrees, 31 degrees, and 26 degrees
Yes, it is a triangle
Can a triangle be formed?
3 in, 7 in, 2 in
small square
triangle where all three sides are equal and all three internal angles are congruent to each at 60 degrees each
Equilateral Triangle
quadrilateral with four right angles
Rectangle
Can a triangle be constructed?
115 degrees, 67 degrees, 10 degrees
No, it is not a triangle.
Can a triangle be formed?
20cm, 30cm, 40cm
Yes, a triangle can be formed.
Arrows
triangle in which one angle is a right angle
Right Triangle
a four-sided shape with two pairs of parallel and two pairs of equal side length
Parallelogram or rectangle
Can a triangle be constructed?
8.7 degrees, 25.5 degrees, 145.8 degrees
Yes, it is a triangle.
Can a triangle be formed?
6 in, 9 in, 2 in
No, a triangle cannot be formed.
What symbol is used to show the same side lengths on a four-sided shape?
Lines or Dashes
triangle where one of the internal angles is greater than 90 degrees but less than 180 degrees
Obtuse Triangle
A four-sided shape that has one pair of parallel sides
Trapezoid
Can a triangle be constructed?
117.6 degrees, 62.4 degrees, 8.4 degrees
No, it is not a triangle.
Two sides of triangle ABC have lengths of 5 cm and 8 cm. What are the possible lengths of the third side?
4,5,6,7,8,9,10,11,12 cm
a closed, two dimensional shape with four straight sides
Quadrilateral
triangle with three angles less than 90 degrees
Acute Triangle
Rhombus
What does x equal?
4x degrees, x degrees, x degrees
30
Two sides of triangle ABC have lengths of 4 inches and 7 inches. What are the possible lengths of the third side?
4,5,6,7,8,9,10 inches