Lesson Worksheet: Angle Sum of a Triangle Mathematics • 8th Grade

Start Practising

In this worksheet, we will practice finding a missing angle in a triangle given the two other angles.

Q1:

The measures of the base angles of an isosceles triangle are (9π‘šβˆ’2𝑛)∘ and (5π‘š+2𝑛)∘, and the measure of the vertex angle is (4π‘š)∘. Find the values of π‘š and 𝑛.

  • Aπ‘š=10, 𝑛=10
  • Bπ‘š=13, 𝑛=13
  • Cπ‘š=10, 𝑛=20
  • Dπ‘š=13, 𝑛=26

Q2:

Complete the sentence: The measure of a straight angle is the sum of the measures of the interior angles of a triangle.

  • Agreater than
  • Bless than
  • Cequal to

Q3:

What is the sum of the measures of the two acute angles in a right-angled triangle?

Q4:

Calculate the value of π‘₯.

Q5:

In triangle 𝐴𝐡𝐢, π‘šβˆ π΄=78∘ and π‘šβˆ π΅=2π‘šβˆ πΆ. What is π‘šβˆ πΆ?

Q6:

Find π‘šβˆ π΄π΅πΆ.

Q7:

The given design is carved on a wooden board. If ∠𝐢 is a right angle, determine the values of π‘₯, 𝑦, and 𝑧.

  • Aπ‘₯=53, 𝑦=82, 𝑧=94
  • Bπ‘₯=36, 𝑦=82, 𝑧=53
  • Cπ‘₯=36, 𝑦=41, 𝑧=94
  • Dπ‘₯=53, 𝑦=41, 𝑧=53

Q8:

Determine the values of π‘₯ and 𝑦.

  • Aπ‘₯=90, 𝑦=90
  • Bπ‘₯=47, 𝑦=43
  • Cπ‘₯=43, 𝑦=47
  • Dπ‘₯=137, 𝑦=133

Q9:

In triangle 𝐴𝐡𝐢, π‘šβˆ π΄=54∘ and π‘šβˆ π΅=71∘. Find π‘šβˆ πΆ.

Q10:

In △𝐴𝐡𝐢, π‘šβˆ π΅=2π‘šβˆ π΄=40∘. Determine π‘šβˆ πΆ.

Practice Means Progress

Download the Nagwa Practice app to access 58 additional questions for this lesson!

scan me!

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.