ABCD is a right-angled trapezoid with area 8. The area of triangle ADB is 5. Then the area of triangle ABC is?

The area of the trapezoid is determined by the formula:

Savsd = (BC + AD) * AB / 2 = 8 cm2.

(BC + AD) * AB = 16 cm2.

BC * AB + AD * AB = 16 cm2. (1).

The area of the triangle ABD is equal to:

Savd = AB * AD / 2 = 5 cm2.

AB * AD = 10 cm2.

Let’s substitute in the first equation.

BC * AB + 10 = 16 cm2.

BC * AB = 6 cm2.

The area of the triangle ABC will be equal to:

Savs = BC * AB / 2 = 6/2 = 3 cm2.

Answer: The area of the triangle ABC is 3 cm2.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.