A right angled triangle.
An acute triangle.
No plane geometric figure can have one acute and three right angle only, at least two other angles must be included
Right angle, obtuse angle, acute angle, supplementary angle, complementary angle, interior angle, exterior angle, adjacent angle
a trapezoid :) * * * * * Not necessarily. A trapezoid can have two right angles, one acute and one obtuse angle. A parallelogram which is not a rectangle must have 2 acute and 2 obtuse angles.
A pentagon.
An acute triangle.
No plane geometric figure can have one acute and three right angle only, at least two other angles must be included
Right angle, obtuse angle, acute angle, supplementary angle, complementary angle, interior angle, exterior angle, adjacent angle
a trapezoid :) * * * * * Not necessarily. A trapezoid can have two right angles, one acute and one obtuse angle. A parallelogram which is not a rectangle must have 2 acute and 2 obtuse angles.
A pentagon.
They can be: acute, right angle, obtuse or reflex
Acute < 90°
Any irregular polygon can have an acute angle. A regular triangle (equilateral) has three acute angles. All other triangles must have at least two acute angles. A quadrilateral, other than a rectangle (or square), must have at least one.
1 acute angle = 1 acute angle
A trapezoid has two right angles and one obtuse and one acute angle.
An acute angle has one angle.
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.