horizontally parallel ribs on the cube – this is the answer to the thematic question for grade 6 SD/MI theme 4, sub-theme 1 “Write 4 horizontally parallel ribs on the cube!”.
The cube in question is the IJKL MNOP cube found in the answer to the previous question.
Students are instructed to find the horizontal parallel edge in the figure of the cube.
Before starting to answer questions, bow your head first and pray according to your respective beliefs and religions.
In the previous material you studied flat shapes. What is flat wake? A flat shape is a two-dimensional object that has a circumference/length/width but no volume.
While the shape of a space is a three-dimensional object that has content/space/volume and the sides that limit it.
There are many kinds of shapes, such as spheres, cones, cubes, blocks, and tubes. Well, this time you will answer questions about building a cube space.
A shape is said to be a “cube” if it has the following characteristics:
1. Each side is a square with the same length/width.
2. It has 8 corner points.
3. Has 12 ribs of the same length, each consisting of:
a. Ribs that are vertically parallel.
b. Horizontally aligned ribs.
c. The ribs are parallel to the diagonal.
4. Has 6 sides of the same area, consisting of 3 pairs of opposite sides.
Now you know the characteristics of the cube building, right? Now is the time to test your skills by doing the following questions:
Write 4 horizontally parallel edges on the cube!
Answer:
Previously, you were assigned to make a picture of the IJKL MNOP cube space, here is the picture:
Cube
From the picture above, we can see that there are 4 horizontal ribs facing each other, among which are IJ, KL, MN, and OP.
Examples of Cube Problems
In everyday life we encounter a lot of cube-shaped objects, such as: dice, refrigerators, etc. We can define a cube as a shape that has six square sides. Cube elements:
1. Side
The side of a cube is the boundary area of a cube. The cube has six sides. The six sides are congruent and the same size. In the figure above, the six sides of the cube are
- Downside: ABCD.
- Upside: EFGH.
- Upright side: ABEF, BCFG, CDGH, ADEH.
2. Ribs
The edge of a cube is the line where the two sides of the cube meet. A cube has 12 ribs. In the picture above, the ribs are AB, BC, CD, AD, EF, FG, GH, EH, AE, BF, CG, and DF. Each edge of the cube has the same length.
3. Corner Point
The vertex of a cube is defined as the meeting point between three edges or three sides in the cube. The cube has 8 point corner. The vertices of the cube are A, B, C, D, E, F, G, and H.
4. Side diagonal
The side diagonal of a cube is a line that joins two opposite vertices on each side of the cube. If a straight line is drawn from point A to point F or from point B to point E, then the line AF or BE is the diagonal of the side of the cube ABCD.EFGH. See Figure 1.2. Since each side of the cube contributes at most 2 diagonals, then in a cube there are 12 side diagonals, namely AF, BE, BG, CF, CH, DG, DE, AH, AC, BD, EG, and FH. The side diagonals of a cube have the same length, i.e. a√2 for a cube with side length a.
See Figure 1.2. If the length of edge AB = athen EB = a. ABF is a right triangle. Using the Pythagorean formula, we get:
AF2 = AB2 + BF2
AF2 = a2 + a2
AF2 = 2a2
AF = 2a2
AF = a2
So, the length of the diagonal of a cube whose side length is ais a2
5. Space Diagonal
The space diagonal of a cube is a line segment that connects 2 opposite vertices in a geometric figure. The cube has 4 space diagonals which same lengthand the four meet at a point called the center of the cube. The four diagonals of the space are AG, BH, CE, and DF. If the side length of cube ABCD.EFGH is a, then the length of the diagonal of the cube is . See Figure 1.3.
Consider the right triangle BDH. Length DH = abecause BD is a side diagonal, the length of BD = a2 , so that:
HB2 = BD2 + DH2
HB2 = (a2 )2 + (a)2
HB2 = 2a2 + a2
HB2 = 3a2
HB = 3a2
HB = a3
So, the length of the diagonal of a cube with side a is a3
6. Diagonal plane
The diagonal of a cube is the area that passes through two opposite edges. The cube has six diagonal planes shaped like congruent rectangle. The diagonal areas of the cube ABCD.EFGH are ACEG, BCEH, CDEF, ADFG, ABGH, and BDFH. See Figure 1.4.
Let the side length of cube ABCD.EFGH be a. The quadrilateral BDFH is a rectangle with length BD = a2 and width BF = a. So we can find the area of the diagonal:
LBDFH = a x a2
LBDFH = a22
So, the area of the diagonal of a cube with side length a isa22Cube NetsThe cube net consists of 6 congruent squares. The following is an example of a cube net model:
It turns out that there are 11 kinds of cube nets.
Surface area
Area A = sx s
Area B = sx s
Area C = sx s
Area D = sx s
Area E = sx s
Area F = sx s
So, the surface area of the cube = LA + LB + LC + LD + LE + LF
= 6 x ( sxs )
Surface Area of Cube = 6 x s²
Example :
1. Calculate the surface area of a cube with a side length of 7 cm!Answer :
Surface area of a cube = 6 xs2
= 6 x 72
= 6 x 49
= 294 cm22. Calculate the surface area of a cube if the area of one side is 10 cm2 !Answer :
Area of one side = 10
s2 = 10
Surface area of a cube = 6 xs2
= 6 x 102
= 6 x 100
= 600 cm23. The surface area of the cube is 600 cm2. Calculate the length of the edge of the cube!
Answer :Surface area of a cube = 6 xs2
600 = 6 x s2
s2 = 
s2 = 100
s = 10 cm
Volume Cube ABCD with side length s unit
Area of Base ABCD = side x side
= sx s
= s2
Volume of Cube = Area of Base ABCD x height
= s2 x s
= s3
| Cube Volume with length side s unit is s3 volume unit. |
Problems example1. Calculate the volume of a cube that has a side of 9 cm!Answer :Volume = s3
= 93
= 729 cm3.2. Calculate the volume of a cube if the area of one side is 9 cm2 !Answer :Area of one side = 9
s2 = 9
s = 3 cmVolume = s3
= 33
= 27 cm33. The volume of a cube is 125 cm3. Calculate the length of the edge of the cube!Answer :Volume = s3125 = s353 = s3
s = 5 cm
*Disclaimer: This answer key is only a guide for parents. Students are free to explore using other answers that they feel are correct.***
