Take the second topic as an example: As shown in the figure, angles A and B are both 30 degrees. AC and CB are 97. Make a vertical line CD perpendicular to AB.

According to the characteristics of isosceles triangle, AD=BD. So the length required by AB is 2AD.

Cosine angle A = cosine 30 degrees = 0.866 = AC/DC.

AD = AC/0.866 = 97/0.866 = 1 12.006

AB=2AD=224。

In the same way, the first question, =2× 1÷COS 35 degrees =2.44.