Angles revision….

What is significant about the letters F, Z, C and U in this topic?

Write down the answer in your books, with an illustration if possible.

What about x?

Angles

Interior angles

These are angles inside a polygon.

They add up to (n-2) x 180 where n is the number of sides

Interior angles

What do these angles add up to?

Exterior angles

Add up to 360

Angles on a straight line

Angles to a point

Vertically opposite angles

Parallel Lines

a

77a = 77 because a and 77 make an F.

Parallel Lines

a

77a = 77 because a and 77 make an F.

“F” angles are called corresponding angles

Parallel Lines

a

77

a = 77 because a and 77 make

a Z

Parallel Lines

a

77

a = 77 because a and 77 make

a Z.

“Z” angles are called alternate angles

p.18 Ex2A Q1, 10 – 15p.19 Ex2B Q1, 4, 11, 12

p.20 Q13-15p.21/ 22 Ex2C Q1, 6, 7, 12, 13, 14, 16-20

p.24/ 25 Ex2D Q1, 4, 10, 14, 16p.28 Ex2E Odd Questionsp.30 Ex2F Even Questionsp.32 Ex2G – All questions

Circles

chord

Centre of circle to aChord – meets at

Right angles

tangent

Radius to a tangent – meets at right angles

Cyclic quadrilaterals – Opposite angles add up to 180

An angle subtended by a semi Circle is a right angle

90

Angles from the same point to the middle are twice those

at the circumference

x

2x

Angles in the same segment are equal

xx