帮忙数学啊....高手们

What is the sum of the measures of the interior angles of an octagon?

What is the measure of an interior angle in a equiangular pentagon?

What is the measure of an interior angle in a regular dodecagon?

what is the sum of the measures of the exterior angles of an 11-gon?

what is the sum of the measures of the interior angles of a 13-gon?

五边形内角和 540° （N-2）×180° 内角和公式

miss的角是 110°

外角和都是180

找个英语高手来吧 有些题俺看不懂 帮不上忙了

任意一个五边形的内角和都是540° ？=540°-100°-110°-130°-90°=110°

可以划分为三个三角形，每个三角形角度之和为180，三个总和为540度。

the missing angle is 540-130-100-110-90=110