1. The problem statement, all variables and given/known data Lisa makes a hole in aluminum foil. She wants to know the diameter of the hole. She points a laser through the hole. That picture is what appears on the wall that is 1,25 meters behind the aluminum. the distance between every circle is 8mm. the wave length is 633nm. http://imgur.com/a/kcaPz 2. Relevant equations dsinx=kλ 3. The attempt at a solution 8mm between maximum 1 and 2. so I know that Tanx= 0.0008/1.25 x= arcTan(0.008/1.25) d=kλ/sinx d= 1*633*10-9/(sin(arcTan(0.008/1.25)) I get the wrong answer, why?