Answer: 12 feet
Step-by-step explanation: look at the bottom length of the rectangle, it is 10 feet, the missing length of the rectangle should be 10 ft as well. we already know that two of the sides are 3 so we can do 3+3+x=10, x=4. the base of the triangle is 4. We can now use the formula for area of the triangle, 1/2 base*height so 1/2 *6*4= 12 feet, Hope this helps!
