A picture 17 inches by 20 inches is to be mounted on a piece of matboard so that there is an even amount of mat all around the picture. How wide will the border be if the area of the mounted picture is 598 square inches?

Question

A picture 17 inches by 20 inches is to be mounted on a piece of matboard so that there is an even amount of mat all around the picture.  How wide will the border be if the area of the mounted picture is 598 square inches?

amistre64 · Answer

17x(20x) = 598 right?

amistre64 · Answer

or rather:

(17+2x)(20+2x) = 598

anonymous · Answer

yes. i need the width of the border

amistre64 · Answer

340 +40x +34x +4x^2

340 +74x +4x^2

x = -74/16 + sqrt(74^2 -4(4)(340))/16 then

amistre64 · Answer

16 meant 8 lol

amistre64 · Answer

lets me test 8.5

anonymous · Answer

test 8.5?

amistre64 · Answer

dint work out as expected :)

amistre64 · Answer

musta missed cued in the calculator; let me try that again

amistre64 · Answer

i forgot to -580

anonymous · Answer

oh. the book gives me a hint that its a solution between 3 and 7 inches

amistre64 · Answer

-598.. i got no short termmemory lately..

amistre64 · Answer

ok, when i do it correctly, I get x=3 so lets try to dbl chk that

anonymous · Answer

3 could be right. thats what i got

amistre64 · Answer

17+2(3) = 23

20 + 2(3) = 26

23(26) = 598, its good

anonymous · Answer

ok. thanks for confirming

anonymous · Answer

medal

amistre64 · Answer

yw :)