Question

Sonali cut a rectangular sheet of paper for her Mathematics project.She cut the sheet whose length and breadth are in the ratio 4:3 and perimeter was 42 cm.She saw that sheet was little smaller.She increased both length and breadth by 2 cm which was of proper size.What was the length of the 1 st rectangle?​

Answer 1

Step-by-step explanation:

Length = 12\frac{1}{2}cm\ =\ \frac{25}{2}cm\

Breadth = 10\frac{2}{3}cm=\frac{32}{3}cm

Perimeter = 2 x (Length + Breadth)

= 2\ \left(\frac{25}{2}+\frac{32}{3}\right)\ =\ 2\left(\frac{\left(25\ \times\ 3\right)+\left(32\ \times2\right)}{6}\right)\ =\ 2\left(\frac{75+64}{6}\right)\

=\ 2\ \times\frac{139}{6}=\frac{139}{3}=46\frac{1}{3}cm

Answer 2

Answer:

Length of first rectangle= 12 cm

Step by step explanation:

We know,

perimeter of rectangle=2 x (length+breadth)... ( 1 )

Let the common factor of the ratio 4:3 be x.

Hence,

Length of rectangle=4x

Breadth of rectangle=3x

From equation ( 1 ),

42 cm = 2 x (4x + 3x)

=> 42 cm = 2 x 7x

=> 42 cm =14x

=>42 cm / 14 = x

=>x = 3 cm

or,

Length of first rectangle= 3 cm x 4 = 12 cm