What is the area to that triangle ?

Answer: 54 cm²
Step-by-step explanation:
Area of the big triangle minus the area of the small triangle will give you the area of the shaded region.
[tex]\text{Area of big triangle}=\dfrac{base\cdot height}{2}\\\\A=\dfrac{24\times 6}{2}\\\\.\quad =12\times 6\\\\.\quad = 72[/tex]
[tex]\text{Area of small triangle}=\dfrac{base\cdot height}{2}\\\\A=\dfrac{12\times 3}{2}\\\\.\quad =6\times 3\\\\.\quad = 18[/tex]
Big - Small = Shaded
72 - 18 = Shaded
54 = Shaded