In order to classify this, you have to be able to find out if one of those is obtuse. A triangle is obtuse if one of the angles is obtuse. The longest side is 32, so we can use the Law of Cosines to make sure that angle C is greater than 90, just to be sure. The LoC for this particular set-up is [tex] c^{2} = a^{2}+ b^{2} -2abcosC [/tex] and solve for C. Filling in our formula we have [tex] 32^{2} = 16^{2}+ 24^{2} -2(16)(24)cosC [/tex] and simplifying gives us 1024=832-768cosC. Subtracting 832 from both sides gives us 192=-768cosC and dividing by both sides gives us -.25=cosC. Using the inverse cos button on our calculator tells us that this angle is 104.47. You should have known that this was an obtuse at the point where you had cosC=-.25 because cos is negative in QII and QIII and our angles there will always be greater than 90. The only angles less than 90, which would be acute, are in QI. Anyway, your triangle is obtuse.
