Question

Q11. A rectangle has a perimeter of 40 cm. If its length is four times as long as its breadth, find its dimensions (i.e. find the width and length of a rectangle) (3 points, 2 minutes)​

Answer 1

Ответ :

Пошаговое объяснение:

Q11 .   Нехай ширина прямокутника має х см , тоді його довжина 4х см .

P = 2( a + b ) ;      2( 4x + x ) = 40 ;

                            2 * 5x = 40 ;

                                 10x = 40 ;

                                    x = 4 см ;    4х = 4 * 4 = 16 ( см ) ;

   a = 16 cм ,   b = 4 cм ;

S = a * b ;       S = 16 * 4 = 64 ( cм² ) ;     S = 64 см² .

Answer 2

Let's denote the width of the rectangle as "w" and the length as "l." According to the problem, we have two pieces of information:

1. The perimeter of the rectangle is 40 cm, which can be expressed as:

   Perimeter = 2(l + w) = 40

2. The length is four times the width, so we can write this as:

   l = 4w

Now, we have a system of two equations:

Equation 1: 2(l + w) = 40 Equation 2: l = 4w

We can solve this system of equations to find the values of "l" and "w." Let's start by substituting the value of "l" from Equation 2 into Equation 1:

2(4w + w) = 40

Now, simplify the equation:

2(5w) = 40

10w = 40

Now, divide both sides by 10 to find the value of "w":

w = 40 / 10 w = 4 cm

Now that we have the width, we can find the length using Equation 2:

l = 4w l = 4 * 4 l = 16 cm

So, the width of the rectangle is 4 cm, and the length is 16 cm.