There isn't a picture of a pattern to go by.
This is a way to factoring trinomials (there exist different equivalent methods).
Multiply the trinomial but the term accompanying . This is the second line. Then, you could take the square of the 
, ant try to create a factor () () that will correspond to the expression in the second line. That is, we want 
In ? we put the corresponding numbers that, if we multiply them we will obtain 42, and if we add them we will obtain 13. This numbers are 6 and 7. Then, we have 
The last step is divide by the number that we multipy in the first step.
I think the answer is 9.3, but I’m not sure
The shape of the cross section is a triangle. Therefore, the answer is the second option: Triangle.
A rectangular pyramid is a pyramid that has a rectangle as its base. Therefore, its base has four sides. The rectangular pyramid also has four triangles that coming together in its apex. So, if the rectangular pyramid is<span> sliced so the cross section is perpendicular to its base and passes through its vertex, the cross section obtained is a triangle.</span>
Sine = opposite / adjacent.
since the opposite and adjacent lines are used, you need to use some to solve for x.
the answer is sine.
