We know that the area A of a triangle is given by
![A=(1)/(2)bh](https://img.qammunity.org/2023/formulas/mathematics/high-school/9sstqki54txhbml6j22rcfvxwdjny9xtib.png)
where b is the base and h is the height.
Now in our case the area A = 15 in^2, h = 6 in, and b = x; therefore, the above equation gives
![15=(1)/(2)\cdot6\cdot x](https://img.qammunity.org/2023/formulas/mathematics/college/poryb6f0vtab15sd2x2bwlku7508lqij1m.png)
multiplying both sides by 2 gives
![30=6x](https://img.qammunity.org/2023/formulas/mathematics/college/u1kjojey1uj9iiavoym7ccc27luut0zj1o.png)
Finally, dividing both sides by 6 gives
![x=(30)/(6)](https://img.qammunity.org/2023/formulas/mathematics/college/pchrilogji770our9beutvkc70plrylj8t.png)
![x=5](https://img.qammunity.org/2023/formulas/mathematics/college/8424ptidkrqocakuhf6dono7i2squ3g3qw.png)
Hence, x = 5 in, which is our answer!