Accepted Answer
You haven't told us whether 9 and 12 are the two legs of the triangle, or whether the 12yd is the longest side.If the 9 and the 12 are the two legs, then:C² = A² + B²C² = 81 + 144C² = 225C = 15 ydIf the 12 is the longest side, then:(12)² = (9)² + B²B² = (12)² - (9)² = 144 - 81 = 63B = √63 = 7.937yd (rounded)