Geo_Book_Answers

LESSON 11.3
1. 16 m
2. 4 ft 3 in.
3. 30 ft
4. 10.92 m
5. 5.46 m
6. Thales used similar right triangles. The height of
the pyramid and 240 m are the lengths of the legs of
one triangle; 6.2 m and 10 m are the lengths of the
corresponding legs of the other triangle; 148.8 m.
7. 90 m; R and O are both right angles and
P is the same angle in both triangles, so
PRE POC by AA.
8. 300 cm
9.
3 cm
t
2 cm
20 cm
y
h
d
x
45 cm
30 cm
Possible answer: Walk to the point where the guy
wire touches your head. Measure your height, h;
the distance from you to the end of the guy wire, x;
and the distance from the point on the ground
directly below the top of the tower to the end of the
guy wire, y. Solve a proportion to find the height of
the tower, t: h
t x .Finally,use y the Pythagorean
Theorem to find the length of the guy
wire: t2 y2
.
10. The triangles are similar by AA (because the
ruler is parallel to the wall), so Kristin can use the
length of string to the ruler, the length of string to
the wall, and the length of the ruler to calculate the
height of the wall; 144 in., or 12 ft.
11. MUN MSA by AA; x 31 2
3 .
12. BDC AEC by AA; y 63.
6
13. GHF FHK GFK by AA; h 18, 13
9 4
x 7, 13
y 44. 13
14. sample answer:
A 1
(8.2)(1.7)
2
6.97 cm2
A 1
(3)(4.6)
2
6.9 cm2
3 cm
15. 5 2
3
16.
D
Given: Parallelogram ABCD
Show: AB CD and AD BC
AD BC
CPCTC
1.7 cm
4
BD BD
Same segment
A
3
Given
8.2 cm
4.6 cm
ABCD is a parallelogram
AD BC
Definition of
parallelogram
2 4
AIA Conjecture
ABD CDB
ASA
17a. 4.6.12
17b. 3.12.12 or 3.12 2
1
C
2
B
AB CD
Definition of
parallelogram
1 3
AIA Conjecture
AB CD
CPCTC
ANSWERS TO EXERCISES 127
Answers to Exercises