Find the value of 3 in the triangle shown below.

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°