Question

use the net for the triangular pr the surface area. 10 cm 8 cm 12 cm 8 cm 10 cm 3 cm

Explanation:

Step1: Calculate the area of the triangular faces

The formula for the area of a triangle is $A = \frac{1}{2}bh$. Here, $b = 8$ cm and $h = 3$ cm.
$$A_{triangle}=\frac{1}{2}\times8\times3 = 12\space cm^{2}$$
Since there are 2 triangular faces, $A_{total - triangles}=2\times12 = 24\space cm^{2}$

Step2: Calculate the area of the rectangular faces

There are 3 rectangular faces.

• For the first rectangle with dimensions $10\times3$: $A_{1}=10\times3 = 30\space cm^{2}$
• For the second rectangle with dimensions $12\times3$: $A_{2}=12\times3 = 36\space cm^{2}$
• For the third rectangle with dimensions $10\times3$: $A_{3}=10\times3 = 30\space cm^{2}$

$A_{total - rectangles}=30 + 36+30=96\space cm^{2}$

Step3: Calculate the total surface area

The total surface area $A = A_{total - triangles}+A_{total - rectangles}$
$$A=24 + 96=120\space cm^{2}$$

Answer:

$120\space cm^{2}$