Page 207 - Start Up Mathematics_6

5. Estimate of area of any closed figure on a squared paper = f + m + h ,
2
where f = number of fully-filled squares, m = number of squares which are more than
half-filled and h = number of half-filled squares. The squares which are less than half-filled
are ignored.

Review Exercises

Multiple ChoiCe Questions
1. If measure of a side of a regular octagon is 6 cm, then its perimeter is:

(a) 48 cm (b) 36 cm (c) 54 cm (d) 56 cm
2. If a ribbon of length 20 cm is stitched around a table cloth making two rounds along its
boundary, then the perimeter of the table cloth is:

(a) 40 cm (b) 20 cm (c) 15 cm (d) 10 cm
3. While estimating the area of an irregular close figure, the contribution of 5 squares (1 cm × 1 cm)
which are less than half-filled is:
5
(a) 10 cm (b) 5 cm (c) cm (d) 0 cm 2
2
2
2
2
4. While estimating the area of a closed figure, the contribution of 8 squares (1 cm × 1 cm)
which are more than half-filled is:
(a) 0 cm (b) 4 cm (c) 8 cm (d) 16 cm 2
2
2
2
5. If the length of a rectangle is doubled and its breadth is halved then its area:
(a) remains same (b) becomes half (c) doubles (d) becomes one-fourth
6. The cost of flooring at ` 20 per square metre is ` 4,200. If the length of the room is 21 m,
then its breadth is:

(a) 5 m (b) 10 m (c) 15 m (d) 20 m

7. If the area of a square is numerically equal to its perimeter, then the length of each side is:
(a) 2 units (b) 3 units (c) 4 units (d) 5 units

8. If two plane figures A and B coincide with each other, then they have:
(a) equal areas (b) equal perimeters

(c) equal area and perimeter (d) none of these

solve Mentally
True or False

1. Perimeter of only closed figures can be found.
2. Two congruent figures (i.e., figures having same size and shape) have equal areas.

3. If the area of a rectangle and a square are equal, then perimeter of the rectangle is less than
that of the square.

4. If a square lies inside a rectangle, then area of the square is less than the rectangle.

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