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A triangle is a three-sided figure with three angles, two or three of which (depending on the triangle) must be acute angles. The sum of all of the angles has to equal 180° - no more, no less. An acute angle is an angle of less than 90°. If one of the angles of a triangle is 90° or more (it is a right angle or obtuse angle) the SUM of the other two angles cannot exceed 180° minus the degree of the first angle. Therefore the two remaining angles must be less than the first angle, which means that they have to be acute angles.
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Do all triangles have two acute angles?
INCORRECT: No because there is a obtuse triangle and a right triangleCORRECT ANSWERYes all triangles have at least two acute angles. Obtuse triangles and right triangles also have at least two acute angles. They are called obtuse triangles and right triangles because by definition they are triangles with ONE obtuse angle and ONE right angle. So therefore they both have 2 acute angles. Also for an acute triangle, it would have 3 acute angles.
Triangle with all angles less than ninety?
In plane geometry, all triangles have the sum of the angles to be 180 degrees. So There are many triangles with all the angles less than 90. ( if one angle is more than 90 degrees, then its called 'obtuse' , if all the angles are less than 90, then its called 'Acute' ). Two types of triangles with angles less than 90 degrees are Equalaterial and Isocoles. ( Equalaterial have two equal angles, Isocoles have three equal angles, all 60 degress ). You can think in terms of sets: The subset of Triangles is Acute, The subset of Acute Triangles is Equalateral, The subset of Equalateral Triangles is Isocoles. {Triangles{Obtuse|Acute{Equlaterial{Isocoles
Are all equilateral triangles acute triangles?
Yes all equilateral triangles are acute triangles, but not all acute triangle are equilateral triangles.
How are acute and obtuse triangles the same?
Similarities between these and all triangles are:They all have 3 sides and 3 angles. The sum of the three angles adds up to 180°.An acute angle is less than 90 degrees. An acute triangle has all three sides are acute.An obtuse angle is more than 90 degrees. An obtuse triangle has one angle which is obtuse, and because of the 180° rule above, the other two angles will be acute.So all triangles will have at least two acute angles.
Can scalene triangles be acute or obtuse?
A scalene triangle can have 1 obtuse angle and 2 different acute angles or it can have 3 different acute angles providing that the 3 angles in both scalene triangles add up to 180 degrees.
