Answer:
15/2
Step-by-step explanation:
Area of a triangle is calculated b*h/2. We know that triangle ADE is 1/4 the size of triangle ABC because AD = 1/4 AB so we can use that to help calculate the base and height of ADE. Base of ABC is 20 if we multiply that by 1/4 we get 5. Height of ACE is 12 if we multiply that by 1/4 we get 3. Plug those numbers into our area equation you get: 5*3/2 or 15/2 or 7.5
