Question

are the triangles below acute, obtuse, or right?
triangle a
triangle b
triangle c
triangle d
40°
80°
30°
45°
30°
110°
50°
50°
35°
115°
45°
acute
acute
acute
acute
obtuse
obtuse
obtuse
obtuse
right
right
right
right

Explanation:

Step1: Recall angle - type definitions

An acute - angled triangle has all angles less than 90°. An obtuse - angled triangle has one angle greater than 90°. A right - angled triangle has one angle equal to 90°.

Step2: Analyze Triangle A

Triangle A has angles 30°, 40°, and 110°. Since 110°>90°, it is an obtuse - angled triangle.

Step3: Analyze Triangle B

Triangle B has angles 50°, 50°, and 80°. All angles are less than 90°, so it is an acute - angled triangle.

Step4: Analyze Triangle C

Triangle C has angles 30°, 35°, and 115°. Since 115°>90°, it is an obtuse - angled triangle.

Step5: Analyze Triangle D

Triangle D has angles 45°, 45°, and 90°. Since one angle is 90°, it is a right - angled triangle.

Answer:

Triangle A: Obtuse
Triangle B: Acute
Triangle C: Obtuse
Triangle D: Right