02 Apr '09 23:41

Given: An isosceles triangle ABC with angles 80 / 20 / 80.

From A draw a straight line at 40 degrees from base to the opposite side. From C draw a straight line at 30 degrees from base to the opposite side.

Connect these opposite side points with a straight line.

Now solve for all interior angles without using trigonometric functions or a protractor. Then prove your answer is correct.

[if you think you can do this with simple algebra, you are mistaken]

From A draw a straight line at 40 degrees from base to the opposite side. From C draw a straight line at 30 degrees from base to the opposite side.

Connect these opposite side points with a straight line.

Now solve for all interior angles without using trigonometric functions or a protractor. Then prove your answer is correct.

[if you think you can do this with simple algebra, you are mistaken]