Term | Definition |
ray | shared by adjacent angles |
sum | the answer to an addition problem |
intersecting lines | lines that cross at a point |
vertical angles | angles which are formed by intersecting lines and have equal measures |
adjacent angles | angles that are next to each other |
supplementary angles | angles whose measures have a sum of 180 degrees |
complementary angles | angles whose measures have a sum of 90 degrees |
acute angle | has a measure less than 90 degrees |
obtuse angle | has a measure more than 90 degrees, but less than 180 degrees |
right angle | has a measure of exactly 90 degrees |
acute triangle | a three sided shape with all angles measuring less than 90 degrees |
right triangle | a three sided shape with one angle measuring exactly 90 degrees |
obtuse triangle | a three sided shape with one angle measuring greater than 90 degrees |
isosceles triangle | a three sided shape with two congruent sides |
equilateral triangle | a three sided shape with all congruent sides |
scalene triangle | a three sided shape with all sides measuring different lengths |
triangle inequality theorem | Helps us to know if three sides will form a triangle. The sum of the two smaller sides, must be greater than the largest side. |
No, 2 + 5 needs to be greater than the third side. | Will sides of 2, 5, and 7 form a triangle? |
No, 4 + 10 needs to be greater than the third side. | Will sides of 4, 15, and 10 form a triangle? |
Yes, 4 + 5 is greater than the third side. | Will sides of 4, 5, and 6 form a triangle? |
2<x<10 | If two sides of a triangle are 6 and 4, give the range of values for the third side. |
180 degrees | What is the sum of all the measures of the angles of a triangle? |
congruent | having exactly the same shape, size or measure |
5<x<11 | If two sides of a triangle are 8 and 3, give the range of values for the third side. |
15<x<55 | If two sides of a triangle are 20 and 35, give the range of values for the third side. |