Question

If angle between two straight lines is acute angle, then angle between their prependiculars will be:

• A. acute
• B. obtuse
• C. right angle
• D. cannot be determined

Answer 1

The correct option is B obtuse

According to figure,
$\angle EDB=\angle EFB={90}^{\circ }$
$\because \angle EDB+\angle DBF+\angle EFB+\angle FED={360}^{\circ }$
or ${90}^{\circ }+\angle DBF+{90}^{\circ }\angle FED={360}^{\circ }$
or $\angle DBF+\angle FED={180}^{\circ }$
According to question,
$\angle DBF$ is acute angle
$\therefore \angle FED$ is obtuse angle.