7. Learning objectives
• define rhombus;
• state the different properties of rhombus;
• apply the theorems of rhombus in solving
problems; and
• appreciate the importance of rhombus in
real-life.
23. It is defined as a parallelogram
with four congruent sides. Just
like the rectangle, it has the
properties of a parallelogram. The
rhombus has special properties as
well.
35. Diagonals bisect each other and are
perpendicular
>
.
FD and AE are diagonals, and
they intersects at Point S
m∠FSA=90°
m∠ASD=90°
m∠DSE=90°
m∠ESF=90°
— —
.
.
.
.
36. Diagonals bisect each other and are
perpendicular
.
4
FADE is a rhombus with
diagonals intersecting at S.
FS + DS = 4 + 4 = 8
The total measurement of FD is
8
—
—
—
37. Diagonals bisect each other and are
perpendicular
.
4
1
2
FADE is a rhombus with
diagonals intersecting at S.
The measurement of AE = 12
AS + ES = 6 + 6 =
12
—
— —
38. Each diagonal bisects a pair of opposite angles.
>
□FADE is a rhombus if and
only FD bisects angle ∠ADE
and ∠AFE
and AE bisects ∠FAD and ∠FED.
—
—
39. Each diagonal separates the rhombus into two
congruent triangles.
>
FD is
diagonal
∆FED≅∆DAF
∆DEF≅∆FAD
—
40. Find the measures of sides if KI=12x and
DN=2(4x+6)
Solve for x:
12x=2(4x+6)
12x=8x+12
12x
2(4x+6)
—
—
.
12x-8x=12
4x=12
4x = 12
_ _
4 4 x=3
41. Find the measures of sides if KI=12x and
DN=2(4x+6)
KI=12x
=12(3)
=36
12x
2(4x+6)
—
—
.
Therefore, all four
sides have a
measurement of 36
42. .
□RICE: Find the measurement of the following if m∠RIC=100
R
I
C
E
a.) m∠REC
b.) m∠ICE
c.) m∠ICR
d.) m∠IEC
43. □RICE: Find the measurement of the following if m∠RIC=100°
R
C
.
I
E
a.) m∠REC
m∠REC = m∠RIC
m∠REC = 100°
44. □RICE: Find the measurement of the following if m∠RIC=100°
R
C
m∠ICE+100° = 180°
.
I
E
b.) m∠ICE
m∠ICE+m∠REC = 180°
.
m∠ICE = 180°-100°
m∠ICE = 80°
45. □RICE: Find the measurement of the following if m∠RIC=100°
R
C
.
I
E
c.) m∠ICR
.
m∠ICR = 1/2 m ∠ICE
m∠ICR = 1/2 (80)
m∠ICR = 40°
46. □RICE: Find the measurement of the following if the
m∠RIC=100° R
C
.
I
E
d.) m∠IEC
.
m∠IEC = 50°
m∠IEC = 1/2 m∠REC
m∠IEC = 1/2 (100)
47.
48. . .
Solve for the unknown value of rhombus.
1. If EH = 21, HG = __________
2. If ∠EFG = 40°, ∠GFH = _________
3. If FH = 12, HI = _________
4. If ∠EHF = 8°, ∠EHG = _________
49. . .
Solve for the unknown value of rhombus.
If ∠HEG = 7x – 1 and ∠FEG = x + 11.
5. x = __________ 8. ∠EGH = __________
6. ∠HEG = __________ 9. ∠EFG = __________
7. ∠FEH = __________ 10. ∠EIH = __________
50.
51. . .
Some of the brand logos make use of the
rhombus geometric shape. For instance, the logo
of Mitsubishi Motors Corporation, a Japanese
multinational automotive manufacturing company
comprises three rhombuses that are attached to
each other at one vertex.
52. . .
Let us use one of the rhombuses of
this brand logo.
58. .
>
>
.
1. In a rhombus ABCD, AB is 5.5
units. What is the measure of AD?
—
A. 3.5
B. 4.5
C. 5.5
D. 6.5
—
59. . .
2. How would you describe the
opposite angles in a rhombus?
A. Opposite angles are congruent.
B. Opposite angles have right angles.
C. Opposite angles are supplementary.
D. Opposite angles are equal to 𝟏𝟖𝟎°.
60. . .
3. In a rhombus, how would you
describe the diagonals?
B. Diagonals have right angles.
C. Diagonals are perpendicular.
D. Diagonals are supplementary.
A. Diagonals are congruent.
61. . .
4. What is the measurement of
BO?
—
A. 9
B. 10
C. 11
D. 12
12
62. . .
5. In rhombus SPEN below, what is
measure of SNE if mSPN is 𝟑𝟓°?
A. 𝟑𝟓°
B. 𝟓𝟓°
C. 𝟕𝟎°
D. 𝟏𝟏𝟎°
.
.
.
.
.
D
63. .
>
>
.
1. In a rhombus ABCD, AB is 5.5
units. What is the measure of AD?
—
A. 3.5
B. 4.5
C. 5.5
D. 6.5
—
64. . .
2. How would you describe the
opposite angles in a rhombus?
A. Opposite angles are congruent.
B. Opposite angles have right angles.
C. Opposite angles are supplementary.
D. Opposite angles are equal to 𝟏𝟖𝟎°.
65. . .
3. In a rhombus, how would you
describe the diagonals?
B. Diagonals have right angles.
C. Diagonals are perpendicular.
D. Diagonals are supplementary.
A. Diagonals are congruent.
66. . .
4. What is the measurement of
BO?
—
A. 9
B. 10
C. 11
D. 12
12
67. . .
5. In rhombus SPEN below, what is
measure of SNE if mSPN is 𝟑𝟓°?
A. 𝟑𝟓°
B. 𝟓𝟓°
C. 𝟕𝟎°
D. 𝟏𝟏𝟎°
.
.
.
.
.
D