A triangle has an area of 221.16 in.² the height of the triangle is 29.1 inches what is the length of the base of the triangle

The formula you should use is Area = 1/2bh, in other words, area equals half times base times height. Now, substitute everything in, the equation should now be 221.16 = 1/2*b*29.1. This simplifies into 221.16 = 14.55b, now divide 14.55 on both sides, which leaves us to 15.2 = b. However, don't forget the units, which the answer (length of base) should be 15.2 in.^2.