- 45 SinceAB
–––
andAD
–––
are tangents to the circle,
they are perpendicular to their respective radii, as
shown. The sum of the angles in a quadrilateral is
360 °, so
m+ 3 m+ 90 + 90 = 360
Simplify: 4 m+ 180 = 360
Subtract 180: 4 m= 180
Divide by 4: m= 45
A C
D
B
m° 3 m°
- 8 Draw the segments shown. Choose point Eto
make rectangle ACDEand right triangle AEB.
Notice that CD=AE,because opposite sides of a
rectangle are equal. You can find AEwith the
Pythagoreantheorem:
(AE)^2 + 62 = 102
Simplify: (AE)^2 + 36 = 100
Subtract 36: (AE)^2 = 64
Take the square root: AE= 8
SinceCD=AE, CD=8.
C
A
B
D
2
2
6
2 8
E
404 McGRAW-HILL’S SAT