Answer:
C
Step-by-step explanation:
We can calculate the area of triangles ABD and DBC, and then add them together to get the area of the whole quadrilateral.

Step-by-step explanation:
The Pythagorean theorem used in right-angled (equilateral) triangles is a relationship between the sides of a right-angled triangle, where the sum of the square of the legs is equal to the square of the hypotenuse.
If a and b are legs, and c is the hypotenuse, then a2 + b2 = c2.
Because the triangle is right angled, there is no greater side length in the triangle, so an unlimited number of Pythagorean positions can be produced by flipping the sides.
Answer:
I guess your answer is 7.722 cm square ......