Answer:
Half the length of the base is 12 cm
Step-by-step explanation:
Assume that the length of the base of the triangle is b and that the height of the triangle is h
We are given that:
Area of triangle is half the base multiplied by the height of the triangle
This means that:
Area of triangle =

Now, we are given that:
Height of triangle = h = 3 cm
Area of triangle = 36 cm²
Substitute with these values in the above equation and solve for half the length of the base
This is done as follows:

From the above, we can conclude that:
Half the length of the base of this triangle is 12 cm
Hope this helps :)