length of a rectangle is 1cm less than 4 times its width. area of the rectangle is 39cm2 whats width and length of the rectangle.

Question

Trying to help my daughter with her homework and we are stuck, any help is appreciated.

 

Thanks

Answer 1

Hi Paul,

 

So we know that the area of a rectangle is length times width.  Let's call the length l and the width w so

 

A=l*w

 

Next we know that the length is 1 cm less (subtraction) than 4 times the width (4w).  Therefore l=4w-1 (1 less than 4 times the width).

 

Now we can substitute this value of l into our original area equation so

 

A=(4w-1)*w=39

 

From here you should be able to distribute and solve for w.  How you solve will depend on the directions since it could be solved by factoring, completing the square, or quadratic formula.

 

Once you have solved for w, use this value in our original l=4w-1 equation to evaluate the length.

 

Hope this helps!