2. Find angles x and y in each figure.
i) As we know, in an isosceles triangle, two sides and the angles they make with the third side are equal. So,
Now, As we know the sum of internal angles of a triangle is 180. so,
Hence, .
ii) As we know, in an isosceles triangle, two sides and the angles they make with the third side are equal.
the sum of internal angles of a triangle is 180. so,
Also,
.
Hence .
iii) As we know when two lines are intersecting, the opposite angles are equal.
the sum of internal angles of a triangle is 180. so,
Now, As we know, the exterior angle is equal to the sum of opposite internal angles in a triangle
Hence .
i) As we know, in an isosceles triangle, two sides and the angles they make with the third side are equal. So,
y+120^0=180^0
y=180^0-120^0
y=60^0
Now, As we know the sum of internal angles of a triangle is 180. so,
x+60^0+60^0=180^0
x=180^0-60^0-60^0
x=60^0
Hence, x=60^0\:\:and\:\:y=60^0.
ii) As we know, in an isosceles triangle, two sides and the angles they make with the third side are equal.
AND
the sum of internal angles of a triangle is 180. so,
x+x+90^0=180^0
2x=90^0
x=45^0
Also,
y=180^0-x
y=180^0-45^0
y=135^0.
Hence x=45^0\:\:and\:\:y=135^0.
iii) As we know when two lines are intersecting, the opposite angles are equal.
And
the sum of internal angles of a triangle is 180. so,
x+x+92^0=180^0
2x=180^0-92^0
2x=88^0
x=44^0
Now, As we know, the exterior angle is equal to the sum of opposite internal angles in a triangle
y=x+92^0
y=44^0+92^0
y=136^0
Hence x=44^0\:\:and\:\:y=136^0.