11.4 Area of Poligons 多边形的面积

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1. P(4, 2), Q(5, 6), R(x, y) and S(-4, 1) are the vertices of a parallelogram PQRS. Find

P(4, 2), Q(5, 6), R(x, y) 和 S(-4, 1) 是一平行四边形PQRS 的顶点, 求

(a) the coordinate of R,

R 的坐标

(b) the area of parallelogram PQRS.

平行四边形PQRS 的面积。

2. ABCD is a rhombus that the coordinates of A, B, C and D are (3, -2), (p, 3), (q, r) and (6, 2) respectively. Calculate

ABCD 是一菱形且A, B, C 和 D 的坐标分别是 (3, -2), (p, 3), (q, r) 和 (6, 2)。求

(a) the values of p, q and r,

p, q 和r的值,

(b) the area of the rhombus.

菱形的面积

3. Coordinates of the vertices A(4, 7), B(0, 5) and C(1, 6) of a triangle, and D is the midpoint of BC. Show that AB + AC = 2AD + BC. Find the area of the quadrilateral OABC, where O is the origin.

一三角形的顶点坐标是A(4, 7), B(0, 5) and C(1, 6), 和 D 是 BC 的中点. 证明AB + AC = 2AD + BC.
求四边形OABC 的面积, 其中 O 是原点