Circles: Circumference, Area, Arcs, Chords, Secants, Tangents, Power of the Point. Theorems. All the links are here

Arc of a Circle Also Central Angles

Area of Circle

$$ \pi \cdot r^2 $$

Central Angle of a Circle

Chord of a Circle

Circumference of Circle

$$ 2\pi \cdot r \\ \pi \cdot diameter $$

Equation of Circle (Standard Form)

Inscribed Angles

Secant of Circle

Tangent of Circle

Circle Calculator

Circle Cal on its own page

Radius
Diameter
Area
Circumference

Status: Calculator waiting for input

$$ $$

Power of the Point

Theorems involving Angles and Arcs

Theorems involving Segments (tangents, secants)

Angle of Tangent & Chord

Product of Segments theorem

Angles & Arcs of Intersecting Chords Intersecting Chords

Circle Calculator

2 Circles, 1 tan, distance?

2 Tans from 1 point

Worksheets and Activities for Math Teachers

Interesting Fact about Circumference and Area

More interesting math facts here!

Big Circle Q

In the accompanying pentgon ABCDE is inscribed in circle o, chords EC and DB intersect at F, chord DB is entended to G and tangent GA is drawn.

Find:

mBDE
mBFC
mAGD

To solve this probelm, you must remember how to find the meaure of the interior angles of a regular polygon. In the case of a pentagon, the interior angles have a measure of (5-2) •180/5 = 108 °. Therefore, each inscribed angle creates an arc of 216°

Use the inscribed angle formula and the formula for the angle of a tangent and a secant to arrive at the angles