Question

4 cm

4 cm
A square-shaped canvas painting was enlarged by adding a 4-centimeter wide decorative frame to the length and width of the canvas. If the area
of the framed painting is 625 square centimeters, what is the side length of the bare canvas?
O A
17 centimeters
OB.
19 centimeters
O c.
21 centimeters
OD
25 centimeters

Answer 1

Let that be x

Now

`\\ \rm\Rrightarrow (x+4+4)^2=625`

`\\ \rm\Rrightarrow x+8=25`

`\\ \rm\Rrightarrow x=25-8`

`\\ \rm\Rrightarrow x=17`

• x is old cube's side before enlargement
• x+8 is side length after enlargement

Option A

Answer 2

17 centimetres

A square has all sides similar.

area of square = side²

• Let the original length be x
• when increased, one side new length → x + 4 + 4 → x + 8

solve:

(x + 8)² = 625

x + 8 = √625

x + 8 = 25

x = 25 - 8

x = 17