Practice 12-1 Tangent Lines
DNG page 485
Assume that lines that appear to be tangent are tangent.
C is the center of each circle. Find the value of x.
x = 180 – 90 – 58
x = 32
x = 360 – 90– 90 –130
x = 50
DNG page 485
Practice 12-1 Tangent Lines
In each diagram,

AB is tangent to C at B. Find the value of x.
3
9
x 2  32  3  7 
2
x 2  9  100
x  91
x  9.54
122  92   x  9
2
225   x  9 
2
225 
 x  92
15  x  9
x6
DNG page 485
Practice 12-1 Tangent Lines

In each diagram,
value of x.
ZY
is tangent to circles O and P. Find the
1
9
3
𝑥 2 = 32 + 252
x 2  9  625
x  634
x  25.18
30
x 2  302  12
x  901
x  30.02
DNG page 485
Practice 12-1 Tangent Lines
Tell whether each polygon is inscribed in or circumscribed about the circle.
circumscribed
about the circle
inscribed
in the circle
In each diagram, a polygon circumscribes a circle. Find the perimeter of each polygon.
4
4
4
5
7
7
6
3
P = 4+5 + 4+3 + 3+5
P = 24 units
5
4
4
P = 4+5 + 12 + 11 + 6+4 +10
P = 52 units
Practice 12-1 Tangent Lines
DNG page 485
Assume that lines that appear to be tangent are tangent.
C is the center of each circle. Find the value of x.
x = 180 – 90 – 58
x = 32
x = 360 – 90– 90 –130
x = 50
x =
360
5
x = 72
DNG page 485
Practice 12-1 Tangent Lines

AB is tangent to C at B. Find the value of x.
In each diagram,
3
9
x 2  82   x  2
x 2  32  3  7 
122  92   x  9
x 2  64  x 2  4 x  4
x 2  9  100
122  92   x  9
2
60  4 x
x  15
2
x  91
x  9.54
2
2
225   x  9 
2
225   x  9
15  x  9
2
x6
DNG page 485
Practice 12-1 Tangent Lines

In each diagram,
value of x.
ZY
is tangent to circles O and P. Find the
1
2
9
3
25
x 2  32  252
x  9  625
2
x  634
x  25.18
1
30
x  30  1
2
2
2
x
x 2  12  7 2
x  901
x  48
x  30.02
x  6.93
DNG page 485
Practice 12-1 Tangent Lines
Tell whether each polygon is inscribed in or circumscribed about the circle.
circumscribed
about the circle
inscribed
in the circle
circumscribed
about the circle
In each diagram, a polygon circumscribes a circle. Find the perimeter of each polygon.
4
6
5
7
3
5
P = 24 units
P = 9 + 8 + 6+5
P = 28 units
5
4
4
5
P = 4+5 + 4+3 + 3+5
7
6
3
3
4
4
P = 4+5 + 12 + 11 + 6+4 +10
P = 52- units
DNG page 485
Practice 12-1 Tangent Lines

AB is tangent to C at B. Find the value of x.
In each diagram,
3
9
x 2  82   x  2
x 2  32  3  7 
122  92   x  9
x 2  64  x 2  4 x  4
x 2  9  100
122  92   x  9
2
60  4 x
x  15
2
x  91
x  9.54
2
2
225   x  9 
2
225   x  9
15  x  9
2
x6
Practice 12-1 Tangent Lines
DNG page 485
Assume that lines that appear to be tangent are tangent.
C is the center of each circle. Find the value of x.
x = 180 – 90 – 58
x = 32
x = 360 – 90– 90 –130
x = 50
x =
360
5
x = 72