This is a rhombus and in any rhombus, the diagonals intersects in the middle and they are perpendicular:
So all 4 triangles are right triangles and the sides are the hypotenuses.
1st) Calculate the sides: hypotenuse² = 3² + 4² = 25, and hypotenuse = 5
The area of each right triangle is (4 x 3)/2 = 6 units²
And the area of the 4 right triangles = 4 x 6 = 24 init²
