Question

Find the unknown angles in the given triangles​

Answer 1

Answer:

Step-by-step explanation:

80 + a + b = 180

here two sides are equal so their opposite angles are also equal so, a=b

Now ,

80 + a + a = 180 ( a=b)

2a=180-80

2a = 100

a = 100/2

a= 50

b=a=50

Answer 2

Solution :-

In this given figure we can see that sides along the 80° angle are equal .

So , the two angles will be equal .

[ Angles opposite to equal sides are equal . ]

Let the measure of each angle be k .

We know in a ∆ the sum of all internal angles is 180° .

⇒ k + k + 80° = 180° .

⇒ 2k = 180⁰ - 80° .

⇒ 2k = 100⁰.

⇒ k = 100° / 2 .

⇒ k = 50° .

So , the values of a and b are equal and equal to 50° .

Now , we also , know that the measure of angle of a straight line is 180° .

So , here

⇒ 50° + x = 180°.

⇒ x = 180° - 50° .

⇒ x = 130⁰.

Here , similarly x = y = 130° .

Hence the values are ,

• a = 50°
• b = 50°
• x = 130°
• y = 130°

More to know :-

• Sum of two sides of a triangle is greater than the third side.
• In isosceles ∆ , two angles are equal.
• In a equilateral ∆ , all three median , angle bisector and perpendicular bisector concide with each other.
• In isosceles ∆ , all three median , angle bisector and perpendicular bisector concide with each other.
• Sides opposite to greater angles are greater.
• Sides opposite to smaller sides are smaller.
• Angles opposite to greater sides are greater.
• Angles opposite to smaller sides are smaller.