Page 257 - Start Up Mathematics_7

9. Area of quadrilateral = Sum of areas of two triangles
1 1
= × d × h + × d × h
2 1 2 2
1
= × (h + h ) × d
2 1 2
Review Exercises

Multiple ChoiCe Questions
1. A farmer wants to fence his rectangular field measuring 14 m by 10 m, one of whose lengths
is along the boundary wall of his house. The required length of the fence is:

(a) 34 m (b) 38 m (c) 48 m (d) 140 m
2. If the base of a triangle is halved and its height is doubled, then the area of the resulting
triangle:
(a) increases (b) decreases (c) doubles (d) remains same

3. The perimeter of a sector of a circle of radius 4 cm and formed by an arc of measure 11 cm
is:

(a) 15 cm (b) 19 cm (c) 30 cm (d) 44 cm
4. A paper is in the form of a rectangle of dimension
21 cm by 15 cm. A semicircle along its length is cut off.
The area of the remaining part is:

2
(a) 173.25 cm (b) 163.25 cm 2 15 cm
2
(c) 141.75 cm (d) 315 cm 2
5. If semicircles are cut off from along each of the two 21 cm
breadths of a rectangle, then the perimeter of the remaining
part is:

(a) 34 cm (b) 68 cm 14 cm
(c) 84 cm (d) 128 cm

6. Two rectangular strips of metal each measuring 50 cm 20 cm
by 10 cm are welded to form a ‘+’ symbol as shown.
This logo is to be painted red on both sides. The surface
area to be painted is:

2
(a) 900 cm (b) 1,000 cm 2
2
(c) 1,800 cm (d) 2,000 cm 2
7. A farmer wishes to cultivate four different crops in equal areas in his 1 are of land. The land
he should allocate for each crop is:

2
2
2
(a) 10 m (b) 25 m (c) 75 m (d) 100 m 2
8. The area of a circular track whose outer and R = 5 m
inner radius is 5 cm and 4 cm is:
2
(a) 41π m (b) 25π m 2 r = 4 m
2
(c) 16π m (d) 9π m 2

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