삼각형과 다각형 단원 종합

K.1Answer each question.

1. 1
   Can sides of $12$, $17$, and $13$ centimeters form a triangle? 
2. 2
   Can sides of $3$, $4$, and $10$ feet form a triangle? 
3. 3
   Can sides of $14$, $17$, and $7$ feet form a triangle? 
4. 4
   Can sides of $19$, $20$, and $44$ feet form a triangle? 

K.2Find each missing angle.

1. 5
   Find the missing angle. 
2. 6
   Find the missing angle. 

K.2Find each missing angle. (continued)

1. 7
   Find the missing angle. 
2. 8
   Find the missing angle. 

K.3K.4Answer each question.

1. 9
   A triangle's angles measure $(x+48{)}^{\circ }$, $x^{\circ }$, and $(2x+40{)}^{\circ }$. Find $x$.
2. 10
   A triangle's angles measure $x^{\circ }$, $(3x+10{)}^{\circ }$, and $(x+30{)}^{\circ }$. Find $x$.
3. 11
   A triangle's angles measure $(x+40{)}^{\circ }$, $(3x+35{)}^{\circ }$, and $x^{\circ }$. Find $x$.
4. 12
   A triangle's angles measure $x^{\circ }$, $(4x+20{)}^{\circ }$, and $(2x+27{)}^{\circ }$. Find $x$.
5. 13
   A trapezoid has two right angles and an angle of $80^{\circ }$. Find its fourth angle.

K.4Answer each question. (continued)

1. 14
   A trapezoid has two right angles and an angle of $126^{\circ }$. Find its fourth angle.
2. 15
   In parallelogram $ABCD$, $m\angle A=45^{\circ }$. Find $m\angle B$.
3. 16
   A trapezoid has two right angles and an angle of $116^{\circ }$. Find its fourth angle.

K.5Count the sides. Use (n − 2) × 180° for the sum of the interior angles.

1. 17
   Regular polygon. Each interior angle: 
2. 18
   Regular polygon. Each interior angle: 
3. 19
   Sum of the interior angles: 
4. 20
   Sum of the interior angles: 

K.1Triangle Inequality

1. 1yes
2. 2no
3. 3yes
4. 4no

K.2Angles in Triangles

1. 5$20^{\circ }$
2. 6$21^{\circ }$
3. 7$39^{\circ }$
4. 8$34^{\circ }$

K.3K.4Answer each question.

1. 9$x=23$
2. 10$x=28$
3. 11$x=21$
4. 12$x=19$
5. 13$100^{\circ }$
6. 14$54^{\circ }$
7. 15$135^{\circ }$
8. 16$64^{\circ }$

K.5Interior Angles of Polygons

1. 17$90^{\circ }$
2. 18$108^{\circ }$
3. 19$540^{\circ }$
4. 20$1,080^{\circ }$