Parallel lines a and b are crossed by a secant c. Find angle 1 if it is three times smaller than angle 2

1. Let’s denote the degree measure of angle 1 through x.

2. Determine the degree measure of angle 2:

3 * x = 3x.

3. The sum of adjacent angles is equal to 180˚, compose and solve the equation:

3x + x = 180˚;

4x = 180˚;

x = 180˚: 4;

x = 45˚.

4. The degree measure of angle 1 is 45˚.

Answer: The degree measure of angle 1 is 45˚.



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