Question

4 cm

Answer 1

I think the answer is A or D

Answer 2

Answer:

Side of bare canvas = 17 cm

Step-by-step explanation:

Let the original side of square shape canvas painting be x cm

Adding 4 cm wide decorative frame to each side of the canvas.

The area of of frames painting is 625 cm²

Please find the attachment for figure.

Frame added both sides.  New side = (x + 4 + 4)

The new side of painting after added frame = (x + 8) cm

The shape of painting is square.

Area of square shape = side × side

Therefore,

$(x+8)(x+4)=625$

$(x+8)^2=25^2$

Taking square root both sides

$x+8=25$

$=x=25-8$

$x=17$

Hence, the side of the bare canvas is 17 cm