Question 1

Which of the following triangles are obtuse triangles?

Select and check your answer...

Check Answer

Step 1

For triangle I, there is no
internal angle that is >90°. Hence,
this is not an obtuse triangle.

Step 2

As for triangle II, it is not an obtuse
triangle for the same reason as above.

Step 3

As for triangle III, the angle at
vertex A is >90°. Hence, it is an obtuse
triangle.

Step 4

For triangle IV, it is an obtuse
triangle because the angle at vertex C
is >90°

Step 5

Clearly, only triangle III and IV are
obtuse triangles. Therefore, the answer
is C.

To close the steps,
obtuse triangle practice question page