Question

Activity Card
Mathematics
Class : 8
Unit - 7
Ratio
Activity 1
The breadth and length of a rectangle are in the ratio 4:5 and its area is 320 cm? What are
the breadth and length?​

Answer 1

Answer:

1) Solve Q1 or 2, Q3 or 4, Q5 or 6, Q7 or 8, Q9 or 10, Q11 or 12. ... Activity. 1-2 1-3 2-4 3-4. 4-5 4-6 5-6 6-7. Duration (Days) → 6. 7. 5 ... hollow with the ratio of inner diameter to outer diameter as 0.6, calculate.

Step-by-step explanation:

1) Solve Q1 or 2, Q3 or 4, Q5 or 6, Q7 or 8, Q9 or 10, Q11 or 12. ... Activity. 1-2 1-3 2-4 3-4. 4-5 4-6 5-6 6-7. Duration (Days) → 6. 7. 5 ... hollow with the ratio of inner diameter to outer diameter as 0.6, calculate.

Answer 2

Answer:

$\rm { Breadth = 16 \; cm }$

$\rm { Length = 20 \; cm }$

Step-by-step explanation:

As per the provided information in the given question, we have :

• The breadth and length of a rectangle are in the ratio 4:5 and its area is 320 cm².

We have to calculate,

• Breadth and length.

Step 1 : Assume the breadth and length as 4x and 5x .

$\longmapsto \rm { Breadth = (4x) \; cm }$

$\longmapsto \rm { Length = (5x) \; cm }$

Step 2 : Framing an equation through the help f the given information.

As we know that,

$\longmapsto \rm { Area_{(Rectangle)} = Length \times Breadth }$

Henceforth, according to the question,

$\longmapsto \rm { 320 \; cm^2 = 5x \; cm \times 4x \; cm }$

Step 3 : Solving the linear equation in order to calculate the value of x.

$\longmapsto \rm { 320 = 20x^2 }$

Transposing 20 from R.H.S to L.H.S. Since it is in the form of multiplication in R.H.S, it will become in the form of division in L.H.S.

$\longmapsto \rm { \cancel{\dfrac{320}{20}} = x^2 }$

Dividing 320 by 20 in L.H.S.

$\longmapsto \rm { 16 = x^2 }$

$\longmapsto \rm { \sqrt{16} = x }$

Square root of 16 is 4 since 4 × 4 is equivalent to 16.

$\longmapsto \rm { 4 = x }$

Step 4 : Substitute the value of x in the algebraic expressions of the length and the breadth.

$\longmapsto \rm { Breadth = (4x) \; cm }$

Substituting the value of x.

$\longmapsto \rm { Breadth = 4(4) \; cm }$

Multiplying 4 with 4.

$\longmapsto \bf { Breadth = 16 \; cm }$

Now, finding the length.

$\longmapsto \rm { Length = (5x) \; cm }$

Substituting the value of x,

$\longmapsto \rm { Length = 5(4) \; cm }$

Multiplying 5 with 4.

$\longmapsto \bf { Length = 20 \; cm }$

∴ Length and Breadth of the rectangle is 20 cm and 16 cm.