Symbol for “is parallel to”
||
symbol for “is perpendicular to”
|
____
symbol for “is congruent to”
triangle of ABC
∆ ABC
therefore
.
. .
because
. .
.
Right angle
= 90˚
collinear points
lie on the same line
concurrent lines
pass through same point
produced
continued
angles of a straight line
= 180˚
vertically opposite angles
equal
angles at a point
= 360˚
co-interior angles
= 180˚
angle sum of triangle
= 180˚
exterior angle of triangle
= sum of interior opposite angles
angle sum of quadrilateral
= 360˚
angle sum of polygon
S = (n-2) x 180˚
exterior angles of a polygon
= 360˚
exterior angle
180˚ - interior angle
OR
360˚ ÷ number of sides
interior angle
180˚ - exterior angle
number of sides
360˚ ÷ exterior angle
or
angle sum ÷ interior angle
congruent triangles
exactly the same shape and size
tests for congruent triangles