I will mark brainliest if correct please answer fast I will give 10 points to the first person who answers

Answer:
[tex]99\ in^{2}[/tex]
Step-by-step explanation:
Area of any triangle could be always calculated as base length multiplied by the height perpendicular to the aforementioned base divided by 2. Therefore:
A = 18 * 11 / 2 = 198 / 2 = 99