Easy Level Worksheet Questions

Part A: Subjective Questions

Note: Write the answers neatly on a sheet and submit them to your school subject teacher.

(1) What is the sum of the angles of a triangle? °

Excellent! The angle sum property states that the three interior angles of any triangle always add up to exactly 180°.

(2) Find the third angle if two angles are 50° and 60°. °

Perfect! Using the angle sum property: Third angle = 180° - 50° - 60° = 70°.

(3) Name the triangle with all sides equal. triangle

Brilliant! An equilateral triangle has all three sides equal in length.

(4) Name the triangle with one angle equal to 90°. triangle

Great job! A right triangle contains exactly one 90° angle.

(5) What is the longest side of a right triangle called?

Awesome! The hypotenuse is always the longest side in a right triangle and is located opposite the right angle.

(6) If the sides of a triangle are 6 cm, 8 cm, and 10 cm, is it right-angled?

Outstanding! You can verify this using the Pythagorean theorem: 6² + 8² = 36 + 64 = 100 = 10².

(7) Name the triangle with exactly one obtuse angle. triangle

Correct! An obtuse triangle has one angle greater than 90°.

(8) In ΔABC, ∠A = 90°, ∠B = 45°, find ∠C. °

Excellent! Using angle sum property: ∠C = 180° - 90° - 45° = 45°.

(9) Write the triangle inequality property. Sum of any two sides > third sideThe difference of any two sides is greater than the third sideAll sides of a triangle are equal

Perfect! The triangle inequality theorem ensures that the three sides can actually form a closed triangle.

(10) Name the triangle with two equal sides. triangle

Wonderful! An isosceles triangle has exactly two sides of equal length.

Drag each triangle description to its correct classification:

(1) The angles of a triangle are 50°, 70°, and x°. Find x.

Sum of angles = °

50° + 70° + x° = 180°, so x = °

Excellent work! You correctly applied the triangle angle sum property.

(2) Check if 3 cm, 4 cm, and 8 cm can be the sides of a triangle.

3 + 4 = , which is less than

Triangle inequality not satisfiedsatisfied, so, the answer is

Perfect analysis! The sum of any two sides must be greater than the third side for a valid triangle.

(3) If two angles of a triangle are 65° and 75°, find the third angle.

Let the third angle be x.

We know that, sum of angles of a triangle = °

65° + 75° + x = 180°

Therefore, x = °

Great job! You efficiently used the angle sum property to find the third angle.

(4) Check whether a triangle with sides 5 cm, 12 cm, and 13 cm is right-angled.

To check if a triangle is right-angled, you use the Pythagoras theorem condition:

a2 + b2 = c22c

Where 5² + 12²13² = 13²12²

=

So, it is a triangle

Outstanding! Since 5² + 12² = 13², this satisfies the Pythagorean theorem.

(5) If one angle of a triangle is 90° and another is 50°, find the third angle.

Let the third angle be x.

We know that, sum of angles of a triangle = °

90° + 50° + x = 180°

x = °

Perfect! In this right triangle, the third angle is 40°.

Test your understanding with these multiple choice questions:

1. Triangle inequality says sum of two sides is:

(a) Less than third side (b) Greater than third side (c) Equal to third side (d) None

Correct! The sum of any two sides must be greater than the third side for a triangle to exist.

2. The perimeter of a triangle with sides 3 cm, 4 cm, and 5 cm is:

(a) 10 cm (b) 11 cm (c) 12 cm (d) 15 cm

Correct! Perimeter = 3 + 4 + 5 = 12 cm.

3. The type of triangle with all angles less than 90° is:

(a) Obtuse (b) Acute (c) Right (d) Equilateral

Correct! An acute triangle has all angles less than 90°.

4. A triangle with one angle greater than 90° is:

(a) Acute (b) Obtuse (c) Equilateral (d) Right

Correct! An obtuse triangle has one angle greater than 90°.

9. A triangle with all sides different is:

(a) Equilateral (b) Isosceles (c) Scalene (d) Right

Correct! A scalene triangle has all three sides of different lengths.