Answer:
(See explanation for further details)
Step-by-step explanation:
Classification based on sides:
Equilateral - Three sides with same length.
Isosceles - Two sides with same length.
Scalene - No sides with same length.
Classification based on sides:
Acute-Angled - All angles are acute. 
Right-Angled - One angle is right. 
Obtuse-Angled - One angle is obtuse. 
The answer would depend on where the numbers you gave us are on the pyramid. but here is the formula to find the surface area of a prism;
surface area= base x height + 2 x length x side + length x base
i will do the equation for you if you specify which numbers are the base, length, side, and height. or if you attach a photo.
Answer:
<em>Explanation below</em>
Step-by-step explanation:
<u>Angles in a Triangle</u>
There are two basic relations of angles we need to recall:
- Supplementary angles add up to 180°
- Internal angles of a triangle add up to 180°
Note a, b, and c are the internal angles of the triangle. The angle c is what is needed to a+b to complete 180°, thus:
c = 180 - ( a + b )
Also, note c and d are supplementary angles. Again, c is what is needed to d to complete 180°, thus
c = 180 - d
From the two relations above, it follows that:
a + b = d
