Question

what is the length of the rectangle whose breadth is 15 cm and perimeter is 70 cm^2 square.
1. 15cm
2. 20 cm
3. 10 cm
4. 5cm


With explanation ​

Answer 1

$\huge \sf{ \red{ \underline{Question : - }}}$

what is the length of the rectangle whose breadth is 15 cm and perimeter is 70 cm² square.

$\huge{ \boxed{ \underline{ \pink{ \sf{To \: find:-}}}}}$

• The length of rectangle.

Given:-

• Breadth of rectangle is 15 cm
• Perimeter of rectangle is 70 cm².

$\boxed{ \underline{ \green{ \mathfrak{Required \: Answer : - }}}}$

Perimeter of rectangle $= 70 {cm}^{2}$

Formula of perimeter of rectangle $= 2(l + b)$

$\boxed{ \sf \purple {2(l + 15cm) = 70 {cm}^{2} }}$

$l + 15 \: cm = \frac{70}{2}$

$l + 15cm = 35cm$

$l = 35 - 15 = 20$

$\boxed{ \underline{ \orange{ \mathfrak{Therefore \: the \: length \: of \: rectangle \: is \: 20 \: cm}}}}$

$\huge \sf{ \red{ \underline{Verification}}} \checkmark$

Perimeter of rectangel is =$2(l + b)$

Here length is 20 cm and breadth is 15 cm.

$\boxed{ \mathfrak{ \green{Now \: substituting \: the \: values \: of \: length \: and \: breadth}}}$

↣ 2 ×(20 + 15) cm

↣ 2 × 35 cm

↣ 70 cm².

Hence it is proved that the value of length is 20 cm.

Step-by-step explanation:

Learn More Formulas

• Perimeter of square = 4× side
• Area of square= side× side
• Area of rectangle = length × breadth
• Area of triangle = ½ × base × height

Answer 2

Given:

The breadth and perimeter of a rectangle are 15cm and $70cm^{2}$ respectively.

To Find:

Find the length of the rectangle.

Solution:

The perimeter of a rectangle $=2(l+b)$ [ where l and b are length and breadth of the rectangle]

Therefore, $2(l+b) =70$

Now, $b= 15cm$

so, $2(l+15) =70$

or, $(l+15) =\frac{70}{2} =35$

so, $l=35 - 15 = 20$

Therefore, the length of the rectangle is 20cm.