Question

in a rectangle length is 4 less than the thrice to the breadth and its perimeter is 78 cm.find its area​

Answer 1

$\bold{\underline{Given \ perimeter }} = \textbf{78 cm}\\\\\textbf{Let \ the \ breadth \ be \ x. And \ length \ be \ 3x - 4}\\\\\textbf{\fbox{Perimeter \ of \ rectangle = 2(l+b)}}\\\\\textbf{78 = 2(x+3x-4)}\\\\\textbf{78 = 2(4x-4) }\\\\\textbf{78 = 8x-8}\\\\\textbf{78 + 8 = 8x ..... 86 = 8x }\\\\\textbf{86/8=x .... 10.75cm (breadth)}$

$\textbf{Length = 3x - 4 = 3 }$ × $\textbf{10.75 - 4 = 28.25cm}$

$\textbf{\fbox{Area \ of \ rectangle = lb}}$

$\textbf {10.75}$ × $\textbf{28.25 = 303.6875}$ $\bold{cm^2}$

$\textbf{Hope \ it \ helps \ !!}$