Question

Word Survs
EVONÁSe 10E
1. The height of a bookshelf is 30 cm. Three dictionaries of thicknesses
6 cm 4 mm, 7 cm 2 mm and 5 cm 5 mm are placed one on top of the
other on the shelf. How much space is left above the dictionaries​

Answer 1

In a cyclic quadrilateral ABCD, if AB || CD and ∠B = 70°, find the remaining angles.

Solution:

In a cyclic quadrilateral ABCD, AB || CD and ∠B = 70°

∵ ABCD is a cyclic quadrilateral

∴ ∠B + ∠D = 180°

⇒ 70° + ∠D = 180°

⇒ ∠D = 180°-70° = 110°

∵ AB || CD

∴ ∠A + ∠D = 180° (Sum of cointerior angles)

∠A+ 110°= 180°

⇒ ∠A= 180°- 110° = 70°

Similarly, ∠B + ∠C = 180°

⇒ 70° + ∠C- 180° ‘

⇒ ∠C = 180°-70°= 110°

∴ ∠A = 70°, ∠C = 110°, ∠D = 110°