Page 258 - Start Up Mathematics_7

9. Meenakshi is to bend a wire to form a logo of
dimensions as shown in the given figure. The
length of wire required is: 7 cm

(a) 256 cm (b) 128 cm
(c) 84 cm (d) 44 cm 7 cm

solve Mentally

True or False
1. A diagonal divides a parallelogram into two triangles of equal areas.
2. The perimeter of a regular hexagon is 6l, where l is the length of its side.
3. Area of a rhombus is the product of any one side and the corresponding altitude.
4. Two rectangles having equal areas should also have their perimeters equal.
5. Two parallelograms on the same base and having equal perimeters have equal areas.
6. For a given value of perimeter, a circle has the maximum area.
7. If perimeter of a figure increases, then its area also increases.
8. Area of a parallelogram can also be obtained by the product of its two adjacent sides.

9. The perimeter of a semicircle of radius r is (2 + π)r.
22
10. The exact value of π is or 3.14.
7
Fill in the Blanks

1. The area of a square of side 4 cm is ____________.
2. If one side of a parallelogram whose perimeter is 42 cm is 12 cm, the measure of its adjacent
side is ____________.
3. The unit of measurement of area is ________________ while that of perimeter is ____________.
4. If a circle touches all the sides of a square, then the circle is said to be ____________ in the
square and its area is ____________ than that of the square.
5. Circumference of a circle is ______ times its diameter. 4 cm
6. π is an _____________ number.
7. If from a rectangle measuring 10 cm by 6 cm, a triangular 6 cm
region is cut, the area of the remaining part is __________.
1
8. Area of a triangle is × base × _____________. 10 cm
2
2
9. An area of 1 km is equal to ____________ hectares.
10. The area of the adjoining parallelogram is _____________. 6.2 cm
5 cm
Answer in One Word or a Line

1. What is the area of a rectangle measuring 6 cm by 9 cm?
2. What is the perimeter of a square field whose each side measures 16 m?
3. What will be the perimeter of a triangle with sides 5 cm, 6 cm and 7 cm?
4. Which is greater, an are or a hectare? By how much?
5. If π is irrational, why its value is taken as 22 , which is rational?
7
6. If a polygon is inscribed in a circle, whose area is greater, polygon or circle? What about their
perimeters?

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