2. Each internal angle of a regular polygon is 20 larger than its adjacent complementary angle. What is the sum of the internal angles of this polygon? 3. If the minimum internal angle of a polygon is 120, the internal angle is slightly larger than it.
125, and then each internal angle is 5 larger than the previous internal angle, and the ratio of the maximum internal angle to the minimum internal angle is 4: 3. Find the number of sides of this polygon and the degree of the maximum internal angle.
1.
The angle b shown in the figure is equal to the angle d.
So angle a is
360-90-2*70= 130
2.
The complementary angle of the inner angle is (180-20)/4=40.
So the inner angle is 140.
It's Zheng Jiulang
The sum of internal angles is
140*9= 1260
3.
The maximum internal angle is 120/3*4= 160.
The number of sides is
( 160- 120)/5+ 1=9