Cambodia · Grade 7 · Practice Sheet 21

1. 1.

   Find the area of a square with side length 21 cm.

   Formula:Area of a Square

   $A = s^2$

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2. 2.

   Find the mean (average) of these numbers: 23, 54, 67, 22, 54.

   Formula:Arithmetic Mean

   $\bar{x} = \dfrac{\sum x}{n}$

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3. 3.

   A right-angled triangle has legs of 20 cm and 17 cm. Find the length of the hypotenuse.

   Formula:Pythagorean Theorem

   $c = \sqrt{a^2 + b^2}$

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4. 4.

   A value changes from 123 to 85. Find the percentage change (to 2 d.p.).

   Formula:Percentage Change

   $\%\,\text{change} = \dfrac{\text{new} - \text{old}}{\text{old}} \times 100$

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5. 5.

   A circle has a radius of 25 cm. Find its area. (Use π ≈ 3.14159)

   Formula:Area of a Circle

   $A = \pi r^2$

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6. 6.

   A right-angled triangle has legs of 3 cm and 14 cm. Find the length of the hypotenuse.

   Formula:Pythagorean Theorem

   $c = \sqrt{a^2 + b^2}$

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7. 7.

   Convert 9.23 kilometres into metres.

   Formula:Metric Length Conversion

   $1\,\text{km} = 1000\,\text{m}$

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8. 8.

   A car travels 588 km in 7 hours. Find its average speed.

   Formula:Speed

   $v = \dfrac{d}{t}$

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9. 9.

   One item costs ៛ 17.98. Find the total cost of 17 items.

   Formula:Total Cost

   $\text{total} = \text{price} \times \text{quantity}$

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10. 10.

    What is 10% of 200?

    Formula:Percentage of a Quantity

    $\text{result} = \dfrac{p}{100} \times N$

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11. 11.

    A car travels 294 km in 6 hours. Find its average speed.

    Formula:Speed

    $v = \dfrac{d}{t}$

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12. 12.

    Find 1/4 of 80.

    Formula:Fraction of a Quantity

    $\text{result} = \dfrac{a}{b} \times N$

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13. 13.

    Find the perimeter of a rectangle measuring 5 m by 4 m.

    Formula:Perimeter of a Rectangle

    $P = 2(l + w)$

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14. 14.

    A triangle has a base of 12 cm and a height of 22 cm. Find its area.

    Formula:Area of a Triangle

    $A = \tfrac{1}{2} b h$

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15. 15.

    A train moves at 48 km/h for 2.2 hours. How far does it travel?

    Formula:Distance from Speed & Time

    $d = v \times t$

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16. 16.

    One item costs ៛ 23.32. Find the total cost of 19 items.

    Formula:Total Cost

    $\text{total} = \text{price} \times \text{quantity}$

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17. 17.

    Solve for x: 7x + 7 = 49.

    Formula:Solving a Linear Equation

    $x = \dfrac{c - b}{a}$

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18. 18.

    A train moves at 99 km/h for 3.9 hours. How far does it travel?

    Formula:Distance from Speed & Time

    $d = v \times t$

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19. 19.

    One item costs ៛ 12.57. Find the total cost of 17 items.

    Formula:Total Cost

    $\text{total} = \text{price} \times \text{quantity}$

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20. 20.

    A train moves at 43 km/h for 3.7 hours. How far does it travel?

    Formula:Distance from Speed & Time

    $d = v \times t$

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