Cabar Minda

看展开图三步 = tiga langkah membaca bentangan 第一步看展开图有哪些形状、各有几个；第二步想象沿着线把面折起来；第三步说出立体的名字，再判断是不是棱柱。图中的展开图有 6 个一样的正方形，折起来就是正方体，正方体是棱柱。 例子：看到 6 个长方形，两两一样大 → 长方体。 注意：展开图的面数跟立体的面数一样多。

three steps to read a net = tiga langkah membaca bentangan Step one: see which shapes the net has and how many of each. Step two: imagine folding the faces along the lines. Step three: name the solid and decide whether it is a prism. The net in the picture has 6 equal squares, so it folds into a cube, and a cube is a prism. Example: 6 rectangles in matching pairs fold into a cuboid. Watch out: a net has exactly as many faces as the solid it makes.

Mei 的展开图 = bentangan Mei 两个三角形折起来一前一后，是一对一样的底面；三个长方形绕一圈连接它们，成为侧面。底面是三角形、有两个底面，所以是三角棱柱，属于棱柱。 例子：三角形包装的长条饼干盒就是这样折成的。 注意：三角锥（piramid segi tiga）的展开图是 4 个三角形，没有长方形。

Mei's net = bentangan Mei The two triangles fold up to sit at the front and back as a matching pair of bases, and the three rectangles wrap round to join them as the sides. Two triangle bases make a triangular prism, which is a prism. Example: a long biscuit box with triangle ends is folded like this. Watch out: the net of a triangular pyramid is 4 triangles with no rectangles at all.

Arif 的展开图 = bentangan Arif 像扇子的扇形卷起来，会变成一个尖尖的弯曲侧面；小圆形盖在下面当底。这就是圆锥体。圆锥体有曲面，所以不是棱柱。圆柱体的展开图是一个长方形加两个圆形。 例子：用扇形的纸卷起来就能做成派对帽。 注意：名字对了还要判断对“是不是棱柱”。

Arif's net = bentangan Arif The fan-shaped piece rolls up into a pointed curved side, and the small circle closes the bottom as the base. That makes a cone. A cone has a curved surface, so it is not a prism. The net of a cylinder is a rectangle with two circles. Example: rolling a fan-shaped piece of paper makes a party hat. Watch out: getting the name right is not enough; also decide correctly whether it is a prism.

分清两种展开图 = beza dua bentangan 两种展开图都有三角形，很容易搞混。三角棱柱：2 个三角形 + 3 个长方形，共 5 个面，三角形一前一后当底面。三角锥：只有 4 个三角形，折起来三个三角形往上聚成一个尖顶，只有一个底面，所以不是棱柱。 例子：看到中间有一排长方形，就是棱柱的展开图。 注意：数一数三角形有几个：2 个是棱柱，4 个是三角锥。

telling two nets apart = beza dua bentangan Both nets contain triangles, so they are easy to mix up. Triangular prism: 2 triangles + 3 rectangles, 5 faces, with the triangles at the front and back as bases. Triangular pyramid: only 4 triangles; when folded, three of them meet at one top point, leaving just one base, so it is not a prism. Example: a row of rectangles in the middle means a prism net. Watch out: count the triangles: 2 means prism, 4 means triangular pyramid.

配对展开图 = padankan bentangan 十字形、6 个一样的正方形 → 正方体。一个长方形上下各接一个圆 → 圆柱体（长方形卷成弯曲的侧面）。一个正方形四边各接一个三角形 → 金字塔，三角形往上聚成尖顶。6 个长方形、两两一样大 → 长方体。 例子：长方体的展开图也常是十字形，但面有长有短。 注意：正方体和长方体的展开图样子很像，要看面是不是都一样大。

matching nets = padankan bentangan A cross of 6 equal squares → cube. A rectangle with a circle above and below → cylinder, because the rectangle rolls into the curved side. A square with a triangle on each side → pyramid, as the triangles meet at a top point. 6 rectangles in matching pairs → cuboid. Example: a cuboid net is often a cross shape too, but its faces are long and short. Watch out: cube and cuboid nets look alike, so check whether all the faces are the same size.