Geometry几何基础知识及英语词汇
Point点：
Point is always named by a letter. Point A, Point B.
Line线：
Is a t of continuous points; it continues on in both directions; and it has no end.
Ray射线：
Is a line begins at an endpoint; and continues on in one direction without endpoint.
Line gment线段：
Is a piece of a line between two endpoints.
Relationship between two Lines/line gments.
A. Intercting lines相交线
Are two lines that cross or will cross at one point.
B. Perpendicular lines 垂直相交线
Two lines that interct at right angle.
C. Parallel Line/gments 平行线/线段
When two lines/gments have no intercting point.
Angles角：
Four kinds of angles四种角
1. Right angle直角
2. Acute angle锐角
3. Obtu angle 钝角
4. Straight angle平角
Note: Protractor量角器： a device to measure the size of an angle.
Plane figure: 平面图： two dimensions
Polygons多边形: clod plane figure made up of three or more line gments.
1. Triangle 三角形
2. Quadrilateral四边形
3. Pentagon五边形
4. Hexagon六边形
5. Heptagon七边形
6. Octagon八边形
7. Nonagon九边形
8. Decagon十边形
Relationship between two plane figures
● Congruent figures: same shape and same size.
● Similar figures: same shape, may/may not the same size
Triangle: Described by their angles三角形：按角度分类
1. Acute triangle: 锐角三角形a triangle with 3 acute angles.
2. Right triangle直角三角形： a triangle with one right angle.
3. Obtu triangle 钝角三角形：a triangle with one obtu angle.
Triangle: classified by the number of congruent sides they have三角形：按边是否等长分类。
1. Scalene不等边三角形： has no congruent side
2. Isosceles等腰三角形: has two congruent sides.
3. Equilateral 等边三角形: has three congruent sides.
Quadrilaterals四边形的分类：
1. Parallelogram平等四边形： a quadrilateral with both paris of opposite sides parallel and congruent.
2. Rhombus菱形: a parallelogram with four congruent sides.
3. Rectangle长方形：a parallelogram with four right angles.
4. Square 正方形： a parallelogram with four right angles and four congruent sides.
5. Trapezoid 梯形：a quadrilateral with only one pair of parallel sides.
Note: Diagonal 对角线：a line gment that join two vertices of a polygon but is not a side of a polygon.
Circle圆：
A clod plane figure with all points the same distance from the center.
1. Center圆心： Circle is the locus of points equidistant from a given point（center).
2. Radius半径：line gment from center to the point on the circle.
3. Diameter直径：the distance across a circle through its center.
4. Chord弦：line gment between two points on the circle.
5. Arc 弧：arc is part of a circle's circumference
Solid figure 立体图形:
6. Sphere球体:
7. Cylinder圆柱体：A solid with two parallel circular bas.
8. Cone圆锥：A solid with a circular ba and a curved side that ends in one point
9. Cube正方体：
10. Pyramid
11. Prism棱镜: a solid object with two congruent and parallel faces。
Triangular Prism三棱柱：A prism with triangular bas。
Rectangular prism四棱柱:A prism with rectangular bas.
Words:
Faces面: the flat surfaces of a solid figure are calle faces.
Perimeter周长:
Area面积:
Volume体积:
