Answer:
Since the lengths of the two sides are equal (3.5), you can tell that this is an isosceles triangle. So, both of the base angles (55°) must be equal. Additionally, you know that the sum of the three angles in a triangle must equal 180°. Therefore, x would equal 70°.
Here's the math:
55° + 55° = 110°
180° - 110° = 70°
x = 70°
TO VERIFY:
70° + 55° + 55° = 180°