Answer:
#a
This is a cube. Let us find the surface area of the cube now
Surface are of a cube = 6 a²
= 6 × 1.2 × 1.2
= 6 × 1.44
= 8.64 cm²
# b
This is a right trianglular prism.
First you have to find the area of the 2 triangles
Before that,
we have to find the height of the triangle using pythagoras theorem.
Let us solve,
[tex]5^{2} =4^{2} +h^{2} \\25=16+h^{2} \\9 =h^{2}\\\sqrt{9} =h\\3=h[/tex]
Now let us find the area of 2 triangles.
[tex]Area =2*\frac{1}{2} *4*3\\[/tex]
[tex]Area =12mm^{2}[/tex]
Now lets find the total area of 3 rectangles.
( 7 mm × 4 mm) + ( 7 mm × 5 mm) + ( 7 mm × 3 mm )
28 mm² + 35 mm² +21 mm²
= 84 mm²
And now lets find the total surface area of this solid.
12 mm² + 84 mm²
= 96 mm²
Hope this helps you.
Let me know if you have any other questions :-)
