The length of a rectangle is 3cm more than its width and it has an area of 230 square cm. How do you find the width to 1 decimal place?

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Answer 1 · 2015-12-18T03:17:51

#13.7# #"cm"#

The rectangle's length can be written in terms of its relation to the width as follows:

#l=w+3#

Thus, if #A=lw#,

#A=(w+3)w#

#A=w^2+3w#

We also know that the area of the rectangle is #230#, so

#230=w^2+3w#

This is a quadratic equation.

#0=w^2+3w-230#

Use the quadratic formula:

#w=(-3+-sqrt(3^2-4(1)(-230)))/(2(1))#

#w=(-3+-sqrt929)/2#

#w=13.7,color(red)(cancel(color(black)(-16.7#

Eliminate the negative answer since width cannot be negative.