Page 280 - Start Up Mathematics_8 (Non CCE)

Review Exercises

Multiple ChoiCe Questions
1. If the area of a triangle with base x is equal to the area of a square with side x, then the altitude of the
triangle is:
x
(a) (b) x (c) 2x (d) 3x
2
2. If the sides of a triangle are doubled, its area:
(a) remains the same (b) becomes double (c) becomes 3 times (d) becomes 4 times
3. The height of an equilateral triangle is 6 cm. The measure of its side is:

(a) 4 cm (b) 33 cm (c) 43 cm (d) 53 cm
1
2
4. The side of a square whose area is 68 m is:
16
1 3 1 3
(a) 7 m (b) 8 m (c) 8 m (d) 7 m
4 4 4 4
5. The area of an equilateral triangle whose side is a units is:

3 3
2
2
2
(a) 3 a (b) 3a (c) a (d) a 2
4 4
solve Mentally
True or False
1. A square decametre is the standard unit of area.

2
2. Diagonal of rectangle = (length) + (breadth) 2
3. The distance between the two parallel sides of a trapezium is called the height of the trapezium.
2
4. If the area of a trapezium is 34 cm and the length of one of the parallel sides is 10 cm and its height is
4 cm, then the length of the other parallel side is 9 cm.

Fill in the Blanks
1. ______________ of a simple closed figure is the sum of all the sides.
2
2. Area of an equilateral triangle = ______________ (side) .
3. Each of the two parallel sides of a trapezium is called the ______________ of the trapezium.
2
4. The area of a trapezium whose bases are 8 m and 5 m and altitude is 2 m is equal to ____________ m .
Answer in One Word or a Line
1. Give Heron’s formula to calculate the area of a triangle.
2. What is the formula for finding the side of a rhombus?
2
2
3. What will be the equivalent of 6.5 m in cm ?
4. How do you find the area of a regular or irregular polygon?
2
5. What will be the altitude of a triangle whose area is 72 m and base is 4 m?

let’s evaluate

1. The base of a triangular field is 880 m and its height is 550 m. Find the area of the field. Also calculate
the charges for supplying water to the field at the rate of ` 25 per square metre.

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