Chapter 11 Perimeter and Area Exercise 11.2

Question 1.
Find the area of each of the following parallelograms: Solution:
(a) Area of the parallelogram
= base × altitude = 7 cm × 4 cm
= 28 cm2
(b) Area of the parallelogram
= base × altitude = 5 cm × 3 cm
= 15 cm2
(c) Area of the parallelogram
= base × altitude = 2.5 cm × 3.5 cm
= 8.75 cm2
(d) Area of the parallelogram
= base × altitude = 5 cm × 4.8 cm
= 24.0 cm2
(e) Area of the parallelogram
= base × altitude = 2 cm × 4.4 cm
= 8.8 cm2

Question 2.
Find the area of each of the following triangles:  Question 3.
Find the missing values:

Solution:
(a) Area of the parallelogram =b × h
246 = 20 × h (b) Area of the parallelogram = b × h
154.5 = b × 15

(c) Area of the parallelogram = b × h
48.72 = b × 8.4 (d) Area of the parallelogram = b × h
16.38 = 15.6 × h

Question 4.
Find the missing values:

Question 5.
PQRS is a parallelogram. QM is the height of Q to SR and QN is the height from Q to PS. If SR = 12 cm and QM = 7.6 cm. Find:
(a) the area of the parallelogram PQRS
(b) QN, if PS = 8 cm

Solution:
(a) Area of the parallelogram PQRS
= SR × QM (∵ Area = Base × Height)
= 12 cm × 7.6 cm
= 91.2 cm2

(b) Area of the parallelogram PQRS

Question 7.
∆ABC is right angled at A. AD is perpendicular to BC. If AB = 5 cm, BC = 13 cm and AC = 12 cm, find the area of ∆ABC. Also find the length of AD.

Solution:
Area of right triangle ABC