Answer:
Area of triangle DEC = 18.9 square feet
Step-by-step explanation:
Here triangle ABC and DEC are similar triangles.
By similar triangle property,
AB/DE = BE/EC -----------------------(1)
Since AB=20 feet, DE =6 feet and BE = 21 feet , we need to find EC.
So, Plug these values in the equation (1)
We get, 20/6 = 21/EC
EC = 21*6 / 20 = 6.3 feet
Now,we will find area of triangle DEC.
area = 1/2 bh ,
Here b = EC = 6.3 feet
And h = DE = 6 feet
So, Area of triangle DEC = 1/2 * 6.3 * 6 = 18.9 square feet
