Answer:
Exercise 1: The length of the unknown leg is 4 inches.
Exercise 3: The following straws can be used to construct the triangle: b)
, c)
, d)
, e)
, f) 
Exercise 4: Possible options of this exercise: 1) (2, 4, 5), 2) (4, 5, 6), 3) (5, 6, 10), 4) (1, 2, 11), 5) (1, 4, 11), 6) (1, 10, 11)
Step-by-step explanation:
Exercise 1:
Let suppose that triangle represented in the figure is a right triangle, the length of the missing leg is determined by Pythagorean Theorem:
(1)
Where:
- Hypotenuse, in inches.
- Known leg, in inches.
- Unknown leg, in inches.
If we know that
and
, then the length of the unknown leg is:

Since 4 is the least whole number closest to
, then we conclude that the length of the unknown leg is 4 inches.
Exercise 3:
The range of possible lengths for the missing side of the triangle is represented by the following simultaneous inequality:
(2)
Where:
- Greater side, in inches.
- Lesser side, in inches.
- Missing side, in inches.
If we know that
and
, then we have the following range of missing sides:

The following straws can be used to construct the triangle: b)
, c)
, d)
, e)
, f) 
Exercise 4:
Let check each pair to determine possible constructions by means of the inequality used in Exercise 3:
(i) 

Possible choices: 5 inches.
(ii) 

Possible choices: 4 inches, 6 inches.
(iii) 

Possible choices: 5 inches, 6 inches.
(iv) 

Possible choices: None.
(v) 

Possible choices: 2 inches, 6 inches.
(vi) 

Possible choices: 5 inches.
(vii) 

Possible choices: None.
(viii) 

Possible choices: 2 inches, 4 inches, 10 inches.
(ix) 

Possible choices: 6 inches.
(x) 

Possible choices: 5 inches.
Possible options of this exercise: 1) (2, 4, 5), 2) (4, 5, 6), 3) (5, 6, 10), 4) (1, 2, 11), 5) (1, 4, 11), 6) (1, 10, 11)