One of the reasons could be , because he was covering up the negative results and showing only the positive side of it .
<h2> ☞ANSWER☜</h2>
<h3>3D shapes</h3>
- Cube Cuboid
- Sphere Square-based pyramid
- Cylinder Triangular prism
- Pentagonal pyramid Hexagonal prism
<h2> ☞EXPLANATION☜</h2>
<em><u>A solid of revolution is a three-dimensional figure obtained by rotating a two-dimensional figure (or curve) around a straight line (called the axis) that lies in the same plane. ... Since the triangle's interior is shaded, it creates the interior of the cone, creating a solid figure.</u></em>
<em><u>Three dimensional shapes are obtained by rotating the two dimensional shapes. When a circle is rotated we get sphere; when a triangle is rotated we get cone; when rectangle or square is rotated we get cylinder</u></em>
Your answer is C.
Hope this helped.
