Math Problem Statement

Find the value of the unknowns in each shape (a trapezoid and a parallelogram).

Solution

In the given image, we have two shapes (a) and (b), and we are tasked with finding the unknown angles. Let’s break down each shape:

(a) Trapezoid

  • The figure has two given angles: 9898^\circ and 4747^\circ.
  • We need to find aa and bb.

Solution:

  1. Opposite angles of a trapezoid: In a trapezoid, the sum of adjacent angles along the same side is 180180^\circ (since they are supplementary).

    • For aa and 9898^\circ: a+98=180    a=18098=82a + 98^\circ = 180^\circ \implies a = 180^\circ - 98^\circ = 82^\circ

    • For bb and 4747^\circ: b+47=180    b=18047=133b + 47^\circ = 180^\circ \implies b = 180^\circ - 47^\circ = 133^\circ

    Thus, a=82a = 82^\circ and b=133b = 133^\circ.

(b) Parallelogram

  • The figure has one given angle: 5858^\circ.
  • We need to find cc, dd, and ee.

Solution:

  1. Opposite angles of a parallelogram: In a parallelogram, opposite angles are equal, and adjacent angles are supplementary (sum to 180180^\circ).

    • For ee: Since ee is opposite 5858^\circ, we have: e=58e = 58^\circ

    • For cc and dd: These are adjacent angles to 5858^\circ, so they must sum to 180180^\circ: c+58=180    c=18058=122c + 58^\circ = 180^\circ \implies c = 180^\circ - 58^\circ = 122^\circ Similarly, dd is opposite cc, so: d=122d = 122^\circ

    Thus, e=58e = 58^\circ, c=122c = 122^\circ, and d=122d = 122^\circ.

Summary:

  • (a): a=82a = 82^\circ, b=133b = 133^\circ
  • (b): c=122c = 122^\circ, d=122d = 122^\circ, e=58e = 58^\circ

Would you like further details on any of these steps?


Here are some related questions for further practice:

  1. What is the sum of the interior angles of a trapezoid?
  2. How do you prove that opposite angles in a parallelogram are equal?
  3. Can a parallelogram have all angles equal? If so, what type of shape is it?
  4. What are the properties of adjacent angles in a cyclic quadrilateral?
  5. How do you calculate the angles in an isosceles trapezoid?

Tip: In any quadrilateral, the sum of the interior angles is always 360360^\circ.

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Math Problem Analysis

Mathematical Concepts

Geometry
Trapezoids
Parallelograms
Angle properties in quadrilaterals

Formulas

Sum of adjacent angles in a trapezoid = 180°
Opposite angles in a parallelogram are equal
Adjacent angles in a parallelogram sum to 180°

Theorems

Angle sum property of a quadrilateral
Supplementary angles theorem
Opposite angles theorem in parallelograms

Suitable Grade Level

Grades 6-8