Parallel Lines and Angles
What angle relationship is shown when two angles are directly across from each other?
Vertical angles
If two angles are vertical, how do you set up the equation?
set them equal
What is the sum of the interior angles of any triangle?
180 degrees
What shape is formed by all points that are the same distance from a center point?
A circle.
What type of triangle uses the Pythagorean Theorem?
Right triangle.
Name the angle relationship formed when a transversal cuts two parallel lines and the angles are in matching corners.
Corresponding angles
If two vertical angles are labeled 3x+10 and 55 what equation would you write?
3x+10=55
If two angles in a triangle are 40° and 60°, should the third angle be larger or smaller than 70°? Why?
Greater, it should be 80°, and because 80° is greater than 70° than the answer is greater than.
An inscribed angle is located where: inside the circle, on the circle, or outside the circle?
On the circle.
What is the Pythagorean Theorem formula?
a2+b2=c2
If two angles are corresponding, what do we know about their measures?
They are congruent (equal).
If two angles are supplementary and labeled (2x+20) and 60, write the equation (don’t solve).
(2x+20) +60 = 180
What makes an isosceles triangle special?
It has two congruent sides and two congruent base angles.
How does the measure of an inscribed angle compare to its intercepted arc?
It is half the measure of the arc.
In the formula, which side is ccc?
The hypotenuse.
If one angle in a linear pair is 110°, what must be true about the other angle?
They are supplementary / they add to 180°.
How do you decide whether to set angles equal or add them to 180°?
Identify the angle relationship first.
If the base angles of an isosceles triangle are equal, how many times do you use that angle measure when adding to 180°?
Twice.
If an inscribed angle is 30°, will the intercepted arc be larger or smaller?
Larger (60°).
When using the Pythagorean Theorem, what is the first step?
Identify the hypotenuse.
Before solving for x in a parallel-lines problem, what is the FIRST thing you should identify?
The angle relationship.
When you solve for x, what are you finding: an angle or a number that helps you find an angle?
A number that helps you find an angle
When solving triangle problems, what is the last step you usually do?
Subtract from 180°.
What is the first thing you should check in a circle problem: the angle or the arc?
Which one is given.
Why can’t you use the Pythagorean Theorem on every triangle?
Because it only works for right triangles.