Chapter 10 Formulas Flashcards
How do you find the measures of secant-secant, secant-tangent, and tangent-tangent angles?
Find the difference of the intercepted arcs and divide by two
How do you find the measure of a chord-chord angle?
Add up the measure of the intercepted arcs then divide by two
What do we know to be true if two inscribed or tangent-chord angles intercept the same arc?
That their angles are congruent
What do we know to be true if an angle is inscribed in a semicircle?
It is a right angle
What do we know to be true about the sum of the measures of a tangent-tangent angle and its minor arc?
Their sums are 180(th 92)
Based on what we know from th 92, how do we find the measure of a tangent-tangent angle(x)?
Set up a system of equations with:
x= (360-y) -y
x= 180-y
What do we know to be true about quadrilaterals inscribed in circles?
That their opposite angles are supplementary
What do we know to be true about all parallelograms inscribed in circles?
That they must at least be a rectangle
What does theorem 95 state?
That in a chord chord angle, the parts of one chord multiplied by each other are congruent to the parts of the other chord multiplied by each other
What does theorem 96 state?
That in a secant-tangent angle, the outside part of the secant times the whole secant is congruent to the tangent squared
What does theorem 97 state?
That in a secant-secant, the outside part of the first secant times the whole of the first secant is congruent to the outside part of the second secant times the whole of the second secant
What is the arc length formula?
The length of the arc is congruent to the measure of the arc, divided by 360, times the circumference of the circle
What does theorem 78 state?
If two chords of a circle are congruent then they are equidistant from the circles center
What does theorem 79 state?
That if two central angles of the same or congruent circles, then their intercepted arcs are congruent.
What do we know to be true if two arcs of a circle are congruent?
That their central angles are congruent