Answer:
<em>10inches</em> is equal to the base
Step-by-step explanation:
formula for finding the area of a triangle is
<u>½bh</u> 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
<em>9</em><em>*</em><em>x=</em><em>9</em><em>x</em>
therefore:9x=90
we devide both sides by the co-efficient of x which is 9
9 dividing 90 is 10.
<em>therefor</em><em>e </em>x is equal 10