Samacheer Kalvi Class 5 Maths Solutions Term 1 Chapter 1 Geometry Exercise 1.3

Question 1. The angles below 90° and above 0° are called as ______
Answer: Angles that are smaller than 90 degrees but larger than 0 degrees are known as acute angles. These angles look sharp, like the tip of a knife.
In simple words: Angles between 0 and 90 degrees are called acute angles.

🎯 Exam Tip: Remember that acute angles are always "cute" and small.

Question 2. The angles below 180° and above 90° are called as ______
Answer: Angles that are larger than 90 degrees but smaller than 180 degrees are called obtuse angles. These angles look wide open, like an open book.
In simple words: Angles between 90 and 180 degrees are called obtuse angles.

🎯 Exam Tip: Think of obtuse as "large" or "broad" to remember its size.

Question 3. By joining two right angles ______ angle is formed
Answer: When you put two right angles together, side by side, they form a straight angle. A straight angle measures exactly 180 degrees, looking like a straight line.
In simple words: Two right angles together make a straight angle.

🎯 Exam Tip: A right angle is 90 degrees, so two of them make 180 degrees, which is a straight line.

Question 4. The obtuse angle in \( \Delta ABC \) is
(a) \( \angle A \)
(b) \( \angle B \)
(c) \( \angle C \)
Answer: (c) \( \angle C \)
In simple words: Angle C is the obtuse angle in the triangle.

🎯 Exam Tip: To find an obtuse angle in a triangle, look for the angle that appears largest or widest, more than 90 degrees.

Question 5. Hand of a clock at 3.20 shows ______ angle.
Answer: At 3:20 on a clock, the angle formed by the hour and minute hands is an acute angle. This means the angle is smaller than 90 degrees.
In simple words: The clock hands at 3:20 make an acute angle.

🎯 Exam Tip: Always visualize the clock hands to quickly determine if an angle is acute, right, or obtuse.

Question 6. In the following letters, which one forms the right angle in it?
(a) L
(b) K
(c) Z
(d) N
Answer: (a) L
In simple words: The letter 'L' has a right angle.

🎯 Exam Tip: A right angle always looks like an 'L' shape or a perfect square corner.

Question 7. Circle the right angle.
(a) (image of an acute angle)
(b) (image of a right angle)
(c) (image of an obtuse angle)
(d) (image of a straight angle)
Answer: (b) (image of a right angle)
In simple words: Option (b) shows the right angle.

🎯 Exam Tip: Identify a right angle by its characteristic square corner, often marked with a small square symbol.

Question 8. The angle shown in this picture is
(a) more than 120°
(b) Less than 45°
(c) more than 180°
(d) 90°
Answer: (d) 90°
In simple words: The angle in the picture is 90 degrees.

🎯 Exam Tip: Always visually check if an angle is a right angle, then confirm its measurement as 90 degrees.

Question 9. The angle formed by the nail cutter is ______
Answer: When you open a nail cutter slightly, the angle formed by its two parts is an acute angle. This means it is a sharp angle, less than 90 degrees.
In simple words: A nail cutter forms an acute angle when open.

🎯 Exam Tip: Think of everyday objects like scissors or nail cutters to visualize different types of angles.

Question 10. Name the angles formed when the vessels are lifted by tongs in the kitchen.
Answer: When you use tongs to lift vessels, the angle created between the two arms of the tongs is an obtuse angle. This angle is wider than 90 degrees as the tongs open up.
In simple words: Tongs create an obtuse angle when used to lift things.

🎯 Exam Tip: Observe how everyday tools and objects create angles to help understand angle types better.