If triangle def has a 90° angle at vertex e, which statements are true? check all that apply.

triangle def is an obtuse triangle.
the angle at vertex d is acute.
the angle at vertex f is obtuse.
triangle def is a right triangle.
the angle at vertex d is obtuse

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

Triangle DEF is a right triangle, because has an angle equal to

case B) The angle at vertex D is acute

The statement is true

Because

∠D+∠F=

so

Angle D is less than

case C) The angle at vertex F is obtuse

The statement is false

Because

∠D+∠F=

so

Angle F is not greater than

case D) Triangle DEF is a right triangle

The statement is true

Because, angle at vertex E is equal to

case E) The angle at vertex D is obtuse

The statement is false

Because

∠D+∠F=

so

Angle D is not greater than

d.192

step-by-step explanation:

12*16=192