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If angle 2 measures 155 degrees in the image below, what is the measurement of angle 1?

User Dsan
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Answer:

diagram of truss with some angles missing

What are the measures of the angles located at positions a, b, & c? Note: the figure is symmetrical on the vertical through angle b.

The large triangle is an isosceles triangle. The two angles on the base are equal. Angle a = 35°

We now know two angles in the largest triangle. The third angle, angle b must add to these to make 180°.

35° + 35° + b = 180°

b = 180° - 70°

b = 110°

We now know two angles in a quadrilateral. The two unknown angles, including angle c are equal. All four angles add up to 360°.

2c + 110° + 120° = 360°

2c = 360° - 230°

2c = 130°

c = 65°

Explanation:

User Mark Bowytz
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