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Find the angle x in each geometric figure.

Geometry worksheet with seven diagrams showing various polygons and angles, each requiring the calculation of the marked angle x.

Geometry worksheet with seven diagrams showing various polygons and angles, each requiring the calculation of the marked angle x.

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Show Answer Key & Explanations Step-by-step solution for: Exterior Angles of Convex Polygons - Opinions Nobody Asked For
To solve for the angle marked \( x \) in each question, we will use geometric properties such as the sum of angles in a triangle, the sum of angles on a straight line, and the properties of parallel lines. Let's go through each problem step by step.

---

Problem 1:


[Diagram shows a quadrilateral with angles \( 80^\circ \), \( 60^\circ \), and \( 70^\circ \). The angle \( x \) is opposite the \( 70^\circ \) angle.]

#### Solution:
The sum of the interior angles of a quadrilateral is \( 360^\circ \). Therefore:
\[
80^\circ + 60^\circ + 70^\circ + x = 360^\circ
\]
\[
210^\circ + x = 360^\circ
\]
\[
x = 360^\circ - 210^\circ = 150^\circ
\]

Answer: \( x = 150^\circ \)

---

Problem 2:


[Diagram shows a quadrilateral with angles \( 130^\circ \), \( 60^\circ \), and \( 110^\circ \). The angle \( x \) is opposite the \( 110^\circ \) angle.]

#### Solution:
Again, the sum of the interior angles of a quadrilateral is \( 360^\circ \). Therefore:
\[
130^\circ + 60^\circ + 110^\circ + x = 360^\circ
\]
\[
300^\circ + x = 360^\circ
\]
\[
x = 360^\circ - 300^\circ = 60^\circ
\]

Answer: \( x = 60^\circ \)

---

Problem 3:


[Diagram shows a triangle with angles \( 50^\circ \), \( 70^\circ \), and an exterior angle of \( 120^\circ \). The angle \( x \) is the third interior angle of the triangle.]

#### Solution:
The sum of the interior angles of a triangle is \( 180^\circ \). Therefore:
\[
50^\circ + 70^\circ + x = 180^\circ
\]
\[
120^\circ + x = 180^\circ
\]
\[
x = 180^\circ - 120^\circ = 60^\circ
\]

Answer: \( x = 60^\circ \)

---

Problem 4:


[Diagram shows a triangle with angles \( 30^\circ \), \( 70^\circ \), and an exterior angle of \( 120^\circ \). The angle \( x \) is the third interior angle of the triangle.]

#### Solution:
The sum of the interior angles of a triangle is \( 180^\circ \). Therefore:
\[
30^\circ + 70^\circ + x = 180^\circ
\]
\[
100^\circ + x = 180^\circ
\]
\[
x = 180^\circ - 100^\circ = 80^\circ
\]

Answer: \( x = 80^\circ \)

---

Problem 5:


[Diagram shows a quadrilateral with angles \( 75^\circ \), \( 120^\circ \), and \( 75^\circ \). The angle \( x \) is the fourth interior angle.]

#### Solution:
The sum of the interior angles of a quadrilateral is \( 360^\circ \). Therefore:
\[
75^\circ + 120^\circ + 75^\circ + x = 360^\circ
\]
\[
270^\circ + x = 360^\circ
\]
\[
x = 360^\circ - 270^\circ = 90^\circ
\]

Answer: \( x = 90^\circ \)

---

Problem 6:


[Diagram shows a quadrilateral with angles \( 25^\circ \), \( 45^\circ \), and \( 95^\circ \). The angle \( x \) is the fourth interior angle.]

#### Solution:
The sum of the interior angles of a quadrilateral is \( 360^\circ \). Therefore:
\[
25^\circ + 45^\circ + 95^\circ + x = 360^\circ
\]
\[
165^\circ + x = 360^\circ
\]
\[
x = 360^\circ - 165^\circ = 195^\circ
\]

Answer: \( x = 195^\circ \)

---

Problem 7:


[Diagram shows a hexagon with angles \( 60^\circ \), \( 120^\circ \), \( 120^\circ \), \( 120^\circ \), and two unknown angles. The angle \( x \) is one of the unknown angles.]

#### Solution:
The sum of the interior angles of a hexagon is given by:
\[
(6-2) \times 180^\circ = 4 \times 180^\circ = 720^\circ
\]
The known angles are \( 60^\circ \), \( 120^\circ \), \( 120^\circ \), and \( 120^\circ \). Let the two unknown angles be \( x \) and \( y \). Therefore:
\[
60^\circ + 120^\circ + 120^\circ + 120^\circ + x + y = 720^\circ
\]
\[
420^\circ + x + y = 720^\circ
\]
\[
x + y = 300^\circ
\]
Since the hexagon is symmetric and the problem asks for \( x \), and there is no indication that \( x \) and \( y \) are different, we assume \( x = y \). Therefore:
\[
x + x = 300^\circ
\]
\[
2x = 300^\circ
\]
\[
x = 150^\circ
\]

Answer: \( x = 150^\circ \)

---

Final Answers:


\[
\boxed{150^\circ, 60^\circ, 60^\circ, 80^\circ, 90^\circ, 195^\circ, 150^\circ}
\]
Parent Tip: Review the logic above to help your child master the concept of interior and exterior angles of polygons worksheet key.
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