Answer:
10inches is equal to the base
Explanation:
formula for finding the area of a triangle is
½bh which is half times base times height
-base is unknown, height is 18 and area is 90.
-½x*18=90
½of 18 is 9
1x*9=90
9*x=9x
therefore:9x=90
we devide both sides by the co-efficient of x which is 9
9 dividing 90 is 10.
therefore x is equal 10