Coaching Centre
Complementary, supplementary and vertically opposite angles
Adjacent angles, complementary and supplementary angles, angles at a point and vertically opposite angles, used to find unknown angles.
Angle pairs
Where two lines cross, neighbouring angles are supplementary and opposite angles are equal.
Finding unknown angles
Angles $x^\circ$ and $38^\circ$ form a right angle. Find $x$.
Angles $2a^\circ$, $100^\circ$ and $110^\circ$ meet at a point. Find $a$.
Two lines cross. One angle is $47^\circ$. Find the other three.
$x^\circ$ and $38^\circ$ are complementary. Find $x$.
$90 - 38$.
$2a^\circ$, $100^\circ$ and $110^\circ$ are at a point. Find $a$.
$2a = 150$.
Two lines cross and one angle is $47^\circ$. Find an angle next to it.
$180 - 47$.
Find the supplement of $65^\circ$.
$180 - 65$.
Find the complement of $72^\circ$.
$90 - 72$.
$x^\circ$, $2x^\circ$ and $72^\circ$ lie on a straight line. Find $x$.
$3x + 72 = 180$, so $3x = 108$.
Vertically opposite angles are:
They are always equal.
Two vertically opposite angles are $3y^\circ$ and $75^\circ$. Find $y$.
$3y = 75$.
New numbers every time. Keep going until you get five in a row.