Answer: 120 cm².
Explanation:
1. To solve this problem you must apply the formula for calculate the area of a triangle, which is:
![A=(b*h)/(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rtg713dvji4p8rrc8goj8f3wvodxpqewuo.png)
Where b is the base and h is the height of the triangle.
2. Then, when you substitute the values given in the problem you obtain:
![A=((4cm)(5cm))/(2)=10cm^(2)](https://img.qammunity.org/2020/formulas/mathematics/high-school/sbhyiy0wfd2mrf9xajh9nbpyj001hebw9z.png)
3. You know that the shape is made of 12 right triangle of equal size, therefore, multiply the area obtained by 12.
4. Then the area of the shape is:
![A_s=12(10cm^(2))=120cm^(2)](https://img.qammunity.org/2020/formulas/mathematics/high-school/touf4gxl14tn1v91oo9q935poxmo0mzc53.png)