Question

Find the total surface area of this triangular prism 21cm 29cm 20cm 22cm

Answer 1

`\huge\boxed{SA=1960cm^2}`

Explanation:

We have:

• 2 rectangular triangles with legs 20cm and 21cm
• 3 different rectangles 20cm × 22cm, 21cm × 22cm and 29cm × 22cm

The formula of an area of

• a rectangular triangle:

`A_\triangle=(a\cdot b)/(2)`

a, b - legs

• a rectangle a × b:

`A_(\square)=a\cdot b`

Calculate:

Rectangular triangle

`A_\triangle=(20\cdot21)/(2)=210(cm^2)`

Rectangles:

`A_(\square1)=20\cdot22=440(cm^2)\\\\A_(\square2)=21\cdot22=462(cm^2)\\\\A_(\square3)=29\cdot22=638(cm^2)`

Total surface:

`SA=2A_\triangle+A_(\square1)+A_(\square2)+A_(\square3)\\\\SA=2\cdot210+440+462+638=1960(cm^2)`