Question

In triangle ABC , BC= AB and <B= 80° , then <A is equal to​

Answer 1

Answer:

=》50°

=》50°Step-by-step explanation:

• =》50°Step-by-step explanation: angle angle angle= 》180°. .
• =》50°Step-by-step explanation: angle angle angle= 》180°. . angle sum property of triangles angle
• =》50°Step-by-step explanation: angle angle angle= 》180°. . angle sum property of triangles angleB =80^ . .... given
• =》50°Step-by-step explanation: angle angle angle= 》180°. . angle sum property of triangles angleB =80^ . .... given angle A= angle C. equal angles of isosceles triangle.
• =》50°Step-by-step explanation: angle angle angle= 》180°. . angle sum property of triangles angleB =80^ . .... given angle A= angle C. equal angles of isosceles triangle. therefore, 80°+ 2( angle A)=180^
• =》50°Step-by-step explanation: angle angle angle= 》180°. . angle sum property of triangles angleB =80^ . .... given angle A= angle C. equal angles of isosceles triangle. therefore, 80°+ 2( angle A)=180^ angleA = 》(180 - 80) / 2
• =》50°Step-by-step explanation: angle angle angle= 》180°. . angle sum property of triangles angleB =80^ . .... given angle A= angle C. equal angles of isosceles triangle. therefore, 80°+ 2( angle A)=180^ angleA = 》(180 - 80) / 2 =》50^

Answer 2

50⁰

As BC=AB

⇒∠A=∠C (As angles opposite to equal sides are equal)

Let the angles be x each.

Now by using angle sum property of triangle

∠A+∠B+∠C=180⁰

⇒x+80⁰+x=180⁰

⇒2x=100⁰

⇒x=50⁰

So ∠A=50⁰