We’re told that QR and RS are equal, so this is an isosceles triangle.
Meaning the two base angles must also be equal
Using this information, we know that the third angle must be 180 - (22 + 22), since the angles in a triangle add up to 180
Meaning the two base angles must also be equal
Using this information, we know that the third angle must be 180 - (22 + 22), since the angles in a triangle add up to 180