A triangle can have:
Only one right or one obtuse angle
The interior angles of a triangle add up to 180°. Examine each option:
Option 1: Two right angles would give \(90^\circ + 90^\circ = 180^\circ\) already, leaving 0° for the third angle. Not possible.
Option 2: One right angle (90°) plus one obtuse angle (> 90°) gives more than 180°. Not possible.
Option 3: A right (90°) or obtuse (> 90°) angle uses at least 90° of the 180° budget, leaving less than 90° to be split between two other angles. So a triangle can have at most one right or one obtuse angle. ✓
Option 4: If each acute angle is > 60°, the total > 180°. Not possible.
Hence the correct statement is Option 3.
Similar Questions
Two right-angled triangular blocks, ABC and DEF, have ∠B = ∠E = 90°. If the lengths of the hypotenuses AC and DF are equal, and the sides AB and DE are equal, are the triangles congruent? If so, by what rule?
- A right-angled triangle ABC has legs AB=6 cm and BC=8 cm. An altitude BD is drawn from the vertex B to the hypotenuse AC. What is the length of the altitude BD?
The ratios of the perimeters of two similar triangles are expressed as 3 : 5. Together, their areas total 34 cm². What is the area of the larger triangle?
A right triangle has sides 3, 4, and 5. A smaller triangle is drawn inside it with its vertices on the sides of the larger triangle, such that it is similar to the larger triangle. If its perimeter is 6, what is its area?
A circle is circumscribed about a triangle. If one of the angles of the triangle is 120°, and the radius of the circumscribed circle is r, what is the length of the side opposite the 120° angle?
In triangle ABC, medians AD, BE, and CF intersect at the centroid G. What is the ratio of the area of triangle GAB to the area of triangle ABC?
In △ABC, a line segment DE is parallel to BC, with D on AB and E on AC. If the ratio of the area of △ADE to the area of the trapezoid DECB is 4 : 21, what is the ratio of AD to DB?
- In an urban project, triangular plots with side ratios 3:4:5 are allocated. If the perimeter is 60 m, find the area.
- In $\Delta ABC \sim \Delta XYZ$ and $AB = 4 \text{ cm}, BC = 6 \text{ cm}, XY = 8 \text{ cm}$, what is the length of YZ?
- The Incenter of a triangle is located at $(3, 4)$. The length of the altitude from the Incenter to side AB is $2\text{ units}$. What is the radius of the triangle's incircle?
Important Questions from Triangles, Congruence and Similarity
If sides of a triangle are 12 cm, 15 cm and 21 cm, then what is the inradius (in cm) of the triangle?
What is the area of quadrilateral ABCD?
It is given that ΔABC ~ ΔXYZ and Area ΔABC : Area ΔXYZ = 81 : 25. If AB = 18 cm, BC = 10 cm, CA = 15 cm, then what is the side XZ (in cm)?
Sides of two similar triangles are in the ratio 4 ∶ 9. Area of these triangles are in the ratio:
If the ratio of corresponding sides of 2 similar triangles is 2 ∶ 3. Then the ratio of their corresponding altitude is :
