Answer:
The answer is
The angle at vertex D is acute
Triangle DEF is a right triangle
Step-by-step explanation:
Statements
case A) Triangle DEF is an obtuse triangle
The statement is false
The triangle DEF has no angle greater than [tex]90\°[/tex]
Triangle DEF is a right triangle, because has an angle equal to [tex]90\°[/tex]
case B) The angle at vertex D is acute
The statement is true
Because
∠D+∠F= [tex]90\°[/tex]
so
Angle D is less than [tex]90\°[/tex]
case C) The angle at vertex F is obtuse
The statement is false
Because
∠D+∠F= [tex]90\°[/tex]
so
Angle F is not greater than [tex]90\°[/tex]
case D) Triangle DEF is a right triangle
The statement is true
Because, angle at vertex E is equal to [tex]90\°[/tex]
case E) The angle at vertex D is obtuse
The statement is false
Because
∠D+∠F= [tex]90\°[/tex]
so
Angle D is not greater than [tex]90\°[/tex]
