A wooden mirror frame is 30 centimeters wide and 50 centimeters tall. If the area of the mirror in the frame is 684 square centimeters, how many centimeters wide is the border surrounding the mirror?

Answer 1

30x50 - 684

= 1500-684

= 816 square cm = the border area

3/5 = ratio of width to height of the frame = ratio of width to height of the picture, A=wh, h=A/w

= w/h = w/A/w = w^2/A = w^2/684 = 3/5

w^2 =3(684)5 = 2052/5 = 412.4

w = sqr412.4 = about 20.3 cm

30-20.3 = 9.7 cm wide border

o

divide by 2

then 4.875 cm wide border

wouldn't hurt to draw a rough sketch of the mirror and border