The formula for the area of a triangle is area= [tex] \frac{1}{2} base*height[/tex] . So when you plug in the given values: Area= [tex] \frac{1}{2} *15 \frac{1}{4}*18[/tex] . When you convert all the numbers to fractions: Area= [tex] \frac{1}{2} * \frac{61}{4} * \frac{18}{1} [/tex] . You multiply across the numerators and divide by the product of the denominators and get 137.25 [tex] inches^{2} [/tex].