Unit 2
Akal Pintar
Mei Ling melukis sebuah segi empat sama PQRK pada satah Cartes.
Dia tahu koordinat P, Q dan R. Di manakah bucu K?

找第四个顶点 = cari bucu keempat
这是一道动脑题。一个正方形有四个顶点,题目只给了三个顶点的坐标,要我们推出最后一个顶点在哪里。关键是记得正方形四条边一样长,而且在方格图上,它的边是横的或竖的。
例子:知道桌子三只脚的位置,就能推出第四只脚应该放在哪里。
注意:推出来以后,要量一量边长,确定真的是正方形。
finding the fourth vertex = cari bucu keempat
This is a thinking puzzle. A square has four vertices; we are given the coordinates of three and must work out where the last one is. The key is that a square's four sides are equal and, on this grid, its sides are horizontal or vertical.
Example: if you know where three legs of a table stand, you can work out where the fourth leg must go.
Watch out: after finding it, measure the sides to make sure the shape really is a square.
Ciri segi empat sama
Sisi mengufuk dan sisi mencancang
P (1, 1) · Q (4, 1) · R (4, 4)
边的方向 = arah sisi
先把已知的三个点画在方格上。P 和 Q 的第二个数字都是 1,所以 PQ 是一条横边,长 3 格;Q 和 R 的第一个数字都是 4,所以 QR 是一条竖边,也是 3 格。正方形对面的边互相平行,所以第四个顶点要和 R 在同一条横线上,和 P 在同一条竖线上。
例子:(2, 5) 和 (6, 5) 的第二个数字相同,它们在同一条横线上。
注意:第二个数字相同 → 横线;第一个数字相同 → 竖线。
direction of the sides = arah sisi
First plot the three known points. P and Q both have second number 1, so PQ is a horizontal side 3 units long; Q and R both have first number 4, so QR is a vertical side, also 3 units. Opposite sides of a square are parallel, so the fourth vertex must be on the same horizontal line as R and the same vertical line as P.
Example: (2, 5) and (6, 5) have the same second number, so they are on the same horizontal line.
Watch out: same second number → horizontal line; same first number → vertical line.
Cari K
x seperti P, y seperti R
K = (1, 4)
K: x = x bagi P = 1 · y = y bagi R = 4 → K (1, 4)
借用两个数字 = pinjam dua nombor
K 在 P 的正上方,所以 K 的第一个数字和 P 一样;K 和 R 在同一条横线上,所以 K 的第二个数字和 R 一样。把这两个数字合起来,就是 K 的坐标 (1, 4)。
例子:一个长方形三个顶点是 (2, 2)、(5, 2)、(5, 6),第四个顶点借 (2, 2) 的第一个数字和 (5, 6) 的第二个数字。
注意:不要把三个点的数字随便加减,要看哪一个点和 K 同一条线。
borrow two numbers = pinjam dua nombor
K is straight above P, so K's first number is the same as P's; K is on the same horizontal line as R, so K's second number is the same as R's. Put the two numbers together and K is at (1, 4).
Example: if a rectangle has vertices (2, 2), (5, 2) and (5, 6), the fourth vertex takes the first number of (2, 2) and the second number of (5, 6).
Watch out: do not just add or subtract the numbers; look at which point shares a line with the missing vertex.
Semak
Empat sisi sama panjang
PQ = QR = RK = KP = 3 unit
PQ: 4 − 1 = 3 · QR: 4 − 1 = 3
RK: 4 − 1 = 3 · KP: 4 − 1 = 3 ✔
RK: 4 − 1 = 3 · KP: 4 − 1 = 3 ✔
验算边长 = semak panjang sisi
横边的长度看第一个数字相差多少,竖边的长度看第二个数字相差多少。四条边都算一次:都是 3 格,四条边一样长,四个角都是直角,所以找到的 K 是对的。
例子:从 (2, 3) 到 (2, 7) 的竖边,长 7 − 3 = 4 格。
注意:如果有一条边长度不同,K 就找错了,要重新检查。
check the side lengths = semak panjang sisi
For a horizontal side, find the difference between the first numbers; for a vertical side, the difference between the second numbers. Work out all four sides: each is 3 units, all equal, with four right angles, so the K we found is correct.
Example: the vertical side from (2, 3) to (2, 7) is 7 − 3 = 4 units long.
Watch out: if any side has a different length, K is wrong and you must check again.
Cuba
Segi empat sama ABCD: A (3, 2), B (5, 2), D (3, 4). Apakah koordinat C?
缺少的顶点 = bucu yang tiada
先找出缺的顶点和哪一个已知点在同一条竖线上,它的第一个数字就借那一个点;再找出它和哪一个已知点在同一条横线上,第二个数字就借那一个点。最后数一数四条边是不是一样长。
例子:正方形三个顶点 (1, 1)、(3, 1)、(1, 3),缺的顶点借 (3, 1) 的第一个数字和 (1, 3) 的第二个数字。
注意:可以先把三个点画在方格上,再看缺的角在哪里。
the missing vertex = bucu yang tiada
Find which known point shares a vertical line with the missing vertex; its first number is borrowed from that point. Then find which known point shares a horizontal line with it; its second number is borrowed from that one. Finally check that all four sides are equal.
Example: for a square with vertices (1, 1), (3, 1) and (1, 3), the missing vertex takes the first number of (3, 1) and the second number of (1, 3).
Watch out: you can plot the three points first to see which corner is missing.
Cuba
Segi empat tepat EFGH: E (1, 3), F (1, 5), G (5, 5). Apakah koordinat H?
长方形的第四个顶点 = bucu keempat segi empat tepat
长方形和正方形一样,对边平行,边是横的或竖的,只是长边和短边不一样长。先看缺的顶点在哪一个已知点的正下方或正上方,借它的第一个数字;再看和哪一个已知点在同一条横线上,借它的第二个数字。
例子:长方形 (0, 1)、(4, 1)、(4, 3),缺的顶点是 (0, 3)。
注意:长方形的长和宽不一定一样,所以不能用“四边一样长”来检查,要检查对边一样长。
the fourth vertex of a rectangle = bucu keempat segi empat tepat
A rectangle, like a square, has parallel opposite sides that are horizontal or vertical; only its long and short sides differ. See which known point the missing vertex is directly above or below, and borrow its first number; then see which known point shares its horizontal line, and borrow its second number.
Example: for the rectangle (0, 1), (4, 1), (4, 3), the missing vertex is (0, 3).
Watch out: a rectangle's length and width can differ, so check that opposite sides are equal rather than all four.
Ringkasan
Syabas!
x sebaris mencancang · y sebaris mengufuk
Bucu yang tiada meminjam nombor pertama daripada bucu di atas atau di bawahnya, dan nombor kedua daripada bucu yang sebaris dengannya.
Latihan tambahan →