Question

The net of an isosceles triangular prism is shown here. What is the surface area, in square units, of the triangular prism?

Answer 1

To do this, find the surface area of each two-dimensional shape. 

The two triangles have a combined area of 24. 

The two rectangles have a combined area of 70.

The center rectangle has an area of 42. 

Add them together to get 136 as your surface area. 

Answer 2

Answer:  Last option is correct.

Step-by-step explanation:

Since we have given that

Dimension of central rectangle is 6 units by 7 units

So, Area of central rectangle is given by

$Length\times breadth=6\times 7=42\ sq.\ units$

Dimensions of upper and lower rectangle are as follows:

Length = 5 units

Breadth = 7 units

Area of upper and lower rectangle is given by

$2\times length\times breadth \\\\=2\times 5\times 7\\\\=70\ sq.\ units$

Similarly, dimensions of two triangles are as follows:

Height = 4 units

Base = 6 units

So, Area of two triangles is given by

$2\times \dfrac{1}{2}\times base\times height\\\\=4\times 6\\\\=24\ sq.\ units$

Hence, Total surface area of the net of an isosceles prism is given by

$42+70+24\\\\=136\ sq.\ units$

Therefore, Last option is correct.