circles lesson 1 april 27 09
TRANSCRIPT
Circle Geometry
diameter
chord
secant
a chord that passes throughthe centre of the circle
a line that contains a chord
a line segment
that joins
two points on
the circle
.
Perpendicular bisector theorem:The perpendicular bisector of a chord contains the centre of the circle. The perpendicular bisectors of two nonparallel chords intersect at the centre of the circle. The perpendicular from the centre of a circle to a chord bisects the cord.
The line segment joining the centre of a circle and the midpoint of a chord is perpendicular to the chord.
A
B
C
O5 3
Find the length of AO, and AB
A
B
C
D
E
O
10
8
Find the length of OE
A chord that is 10 cm long is 12 cm from the centre of a circle. Find the length of the radius.
A road tunnel under a river is built inside a cylinder of radius 5.35 m. The road surface, AB, is 1.85 m above the lowest point of the cylinder. What is the width of the road to the nearest hundreth of a metre?
A B
Questions 1 6
Exercise 30