Consider the following parallelograms. Find the values of the unknowns x, y, z.
Solution:
(i) Since ∠D is opposite to ∠B, so, y = 100° (Opposite angles of a parallelogram are equal)
∠C + ∠B = 180° (The adjacent angles in a parallelogram are supplementary)
x + 100° = 180° (The adjacent angles in a parallelogram are supplementary)
Therefore,
x = 180° - 100° = 80°
x = z = 80° (Since opposite angles of a parallelogram are equal)
Thus, x = 80°, y = 100°, z = 80°
(ii) x + 50° = 180° (The adjacent angles in a parallelogram are supplementary)
x = 180° - 50°
= 130°
x = y = 130° (Since opposite angles of a parallelogram are equal)
x = z = 130° (Corresponding angles)
Thus, x = y = z = 130°
(iii) x + y + 30° = 180°(Angle sum property of a triangle)
x = 90° (Vertically opposite angle)
90° + y + 30° = 180°
y + 120° = 180°
y = 60°
z = y = 60° (Alternate interior angles are equal)
x = 90°, y = z = 60°
(iv) z = 80°(Corresponding angles)
y = 80° (Since opposite angles of a parallelogram are equal)
x + y = 180°(Adjacent angles of a parallelogram are supplementary)
x + 80° = 180°
x = 180° - 80°
x = 100°
Thus, x = 100°, y = 80°, z = 80°
(v) y = 112°(Since opposite angles of a parallelogram are equal)
x + y + 40° = 180° (Angle sum property of a triangle)
x + 112° + 40° = 180°
x + 152° = 180°
x = 180° - 152°
x = 28°
z = x = 28°(Alternate interior angles)
Thus, x = 28°, y = 112°, z = 28°
☛ Check: NCERT Solutions for Class 8 Maths Chapter 3
Video Solution:
Consider the following parallelograms. Find the values of the unknowns x, y, z
NCERT Solutions Class 8 Maths Chapter 3 Exercise 3.3 Question 2
Summary:
In the following parallelograms, the values of the unknowns x, y, z are: (i) The values of x, y and z are 80°, 100° and 80° respectively. (ii) The values of x, y and z are 130°, 130° and 130° respectively. (iii) The values of x, y and z are 90°, 60° and 60° respectively. (iv) The values of x, y and z are 100°, 80° and 80° respectively. (v) The values of x, y and z are 28°, 112° and 28° respectively.
☛ Related Questions:
- Can a quadrilateral ABCD be a parallelogram if (i) ∠D + ∠B = 180°? (ii) AB = DC = 8 cm, AD = 4 cm and BC = 4.4 cm? (iii) ∠A = 70° and ∠C = 65°?
- Draw a rough figure of a quadrilateral that is not a parallelogram but has exactly two opposite angles of equal measure.
- The measures of two adjacent angles of a parallelogram are in the ratio 3:2. Find the measure of each of the angles of the parallelogram.
- Two adjacent angles of a parallelogram have equal measure. Find the measure of each of the angles of the parallelogram.
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