Answer:
W = 10 cm
Explanation:
Area of a Triangle and a Rectangle
The area of a triangle of base B and height H is:
![\displaystyle A_t=(BH)/(2)](https://img.qammunity.org/2022/formulas/mathematics/high-school/hbtx1g7i6mph4yzl7awb39wberpy4fuxb4.png)
The area of a rectangle of width W and length L is:
![A_r=WL](https://img.qammunity.org/2022/formulas/mathematics/high-school/ks1ae1lwm3tqui82qvk744gvn1g40eowma.png)
We are given the base of the triangle B=6 cm and the height H=8 cm, thus the area is:
![\displaystyle A_t=(6*8)/(2)= 24\ cm^2](https://img.qammunity.org/2022/formulas/mathematics/high-school/9e6d399i0dmtrcst4vlshmgwcjy80bgc89.png)
The area of the rectangle is 5 times the area of the triangle, thus:
![A_r=5*24\ cm^2=120\ cm^2](https://img.qammunity.org/2022/formulas/mathematics/high-school/dgj7y1d6s4njnmkgrkf3c54ll3iybdr4dc.png)
If we know the area of the rectangle and its length, we can find the width by solving for W:
![\displaystyle W=(A_r)/(L)](https://img.qammunity.org/2022/formulas/mathematics/high-school/fubt9sqpg5m7jvgykxr52dthon3bj4yed1.png)
The rectangle has a length of L=12 cm, thus:
![\displaystyle W=(120)/(12)=10\ cm](https://img.qammunity.org/2022/formulas/mathematics/high-school/38zdsqopqx42wmhjbgkf8nxcdnoed0e5ae.png)
W = 10 cm