Question

a rectangle with 7cm by 4 1/2cm.​

Answer 1

Step-by-step explanation:

How much wire will be needed to make a rectangle 7 cm long and 4 cm wide? SOLUTION Perimeter of a rectangle = 2 x length + 2 x breadth Page 3 = 2 x 7 + 2 x 4 = 14 + 8 = 22 cm ∴ 22 cm wire will be needed to make a rectangle.

Answer 2

Answer:

Previously the area was: 7∗4=28cm2

Now the area is: (7+x)∗(4+x)=(28+42)=70cm2

Now all we have to do is solve for ‘x’, which was the equal amount by which both sides were increased by.

Expand out the brackets: x2+11x+28=28+42

Now take 28 away from both sides: x2+11x=42

Then take 42 away from both sides: x2+11x−42=0

This is much easier now, all we have to do is factorise and solve for ‘x’:

=>(x+14)(x−3)=0

So ‘x’ is either -14 or 3, but because x is a measure of length it must be a positive number so x is 3.