Question

If 2 of the angles of a triangle are 30 and 70 degrees, the third angle measures ...

Answer 1

Answer:

The third angle measures 80°

Step-by-step explanation:

Let us solve the question

In any triangle

∵ The sum of the measures of the interior angles of a triangle is 180°

∵ The angle of triangles are ∠1, ∠2, and ∠3

∴ m∠1 + m∠2 + m∠3 = 180°

∵ Two of the angles of the triangle are 30° and 70°

∴ m∠1 = 30°

∴ m∠2 = 70°

→ Substitute them in the rule above

∴ 30° + 70° + m∠3 = 180°

→ Add the like terms

∵ (30 + 70) + m∠3 = 180

∴ 100 + m∠3 = 180

→ Subtract 100 from both sides

∵ 100 - 100 + m∠3 = 180 - 100

∴ m∠3 = 80°

∴ The third angle measures 80°