Answer:
10a: △ABC is an Equilateral triangle with all acute angles. 
10b: △BCD is A scalene triangle with all acute angles. 
10c: △BDE is An Isosceles triangle with one obtuse angle.
Step-by-step explanation:
10) Looking at the diagram at the bottom left;
- △ABC has 3 equal internal angles and as such, it means it will have 3 equal angles. 
Thus, we can classify it as; Equilateral triangle with all acute angles.
- △BCD has 3 unequal angles. Thus, it's 3 sides are not equal. Also all the angles are less than 90°.
We can classify it as;
A scalene triangle with all acute angles
- △BDE has 2 equal angles and one angle greater than 90°. This means it has 2 equal sides.
Thus, we can classify it as;
- An Isosceles triangle with one obtuse angle. 
 
        
             
        
        
        
Answer:

General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Algebra I</u>
- Midpoint Formula:  
Step-by-step explanation:
<u>Step 1: Define</u>
A (-3, -5)
B (2, 7)
<u>Step 2: Find midpoint</u>
- Substitute:                     
- Add:                               
- Divide:                           
 
        
             
        
        
        
The range of the function is (-♾, ♾)
        
             
        
        
        
Remark. 
It's true. A line segment has a finite length. A line is infinitely long. It takes a lot of something that is finite to cover something that is infinite. 
________ Suppose this is a part of a line. Just a part mind you.
.................... these are line segments. How many segments will it take to cover a line if you keep on extending the line to the line's "full" length?