Proportional Reasoning 2 Class 8 Very Short Question Answer

Proportional Reasoning 2 Class 8 Very Short Question Answer

Proportional Reasoning 2 Class 8 Very Short Question Answer

Question 1.

Determine if the following is true or not:

99 kg : 45 kg :: ₹ 44 : ₹ 20

Solution:

[latex]\frac{99 \mathrm{~kg}}{45 \mathrm{~kg}}[/latex] = [latex]\frac{11}{5}[/latex]

ans [latex]\frac{₹ 44}{₹ 20}[/latex] = [latex]\frac{11}{5}[/latex]

So, 99 kg : 45 kg : : ₹ 44 : ₹ 20 is true.

Question 2.

Check if the following statement is true or not:

45 kg: 60 km :: 12 hours : 15 hours

Solution:

45 kg : 60 km =[latex]\frac{45}{60}[/latex] = [latex]\frac{3}{4}[/latex]

12 hours : 15 hours = [latex]\frac{12}{15}[/latex] = [latex]\frac{4}{5}[/latex]

So, above statement is not true.

Question 3.

Find whether length (in cm) of the side of a square is in direct proportion to its area (in cm²).

Solution:

Area of the square of sidelength 1 cm is 1 cm², area of the square of sidelength 2 cm is 2 × 2 = 4 cm².

Here [latex]\frac{1}{1}[/latex] ≠ [latex]\frac{1}{4}[/latex]. ([latex]\frac{x_1}{y_1}[/latex] ≠ [latex]\frac{x_2}{y_2}[/latex])

So, length of the side of a square is not in direct proportion.

Question 4.

Find whether the length (in cm) of the side of a square is in direct proportion to its perimeter (in cm).

Solution:

Perimeter of the square of sidelength 1 cm is 4 × 1 = 4 cm and perimeter of the square of sidelength 3 cm is 4 × 3 = 12 cm.

Now, [latex]\frac{1}{3}[/latex] = [latex]\frac{4}{12}[/latex] = [latex]\frac{1}{3}[/latex].

So, length of the side of a square is in direct proportion to its perimeter.

Question 5.

Observe the following table :

Check whether x and y are in inverse proportion.

Solution:

90 × 10 = 900, 60 × 15 = 900 and 45 × 20 = 900, but 30 × 25 = 750.

So, x and y are not in inverse proportion.