Constructions and Tilings | FIO

Question 16

Construct the following figure.

Question diagram 1
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Solution
Understand the Question
  • To construct the given 8-pointed star design:
    1. Draw a circle and divide its circumference into 8 equally spaced points using perpendicular diameters and their angle bisectors.
    2. Join the vertices by skipping two points at a time (connecting each vertex to the third point clockwise) to form the 8-pointed star outline.
    3. Shade the 8 inner triangular regions while leaving the 8 outer star points unshaded.

Step 1 · Draw Base Circle and Divide into 8 Equal Parts

Draw a circle and locate 8 equally spaced points on its circumference.Diagram 1

  1. Draw a circle with center OO.
  2. Draw two mutually perpendicular diameters passing through OO to mark 4 equally spaced points.
  3. Bisect the angles between these diameters and extend the bisectors to the circumference to obtain 4 more points.
  4. Label these 8 equally spaced points clockwise as S,T,U,V,W,X,Y,ZS, T, U, V, W, X, Y, Z starting from the top.

Step 2 · Draw Star Outline

Join the points on the circle with straight line segments to form the star.Diagram 2

Draw the following 8 straight line segments:

  • SS to VV
  • TT to WW
  • UU to XX
  • VV to YY
  • WW to ZZ
  • XX to SS
  • YY to TT
  • ZZ to UU

Step 3 · Identify and Shade Required Regions

Shade the inner triangular regions of the star.Diagram 3

  1. Leave the 8 outer triangular points labeled A,B,C,D,E,F,G,HA, B, C, D, E, F, G, H unshaded (white).
  2. Carefully shade the 8 inner triangular regions forming the body of the star to match the given pattern.
Answer

The 8-pointed star figure is constructed and shaded as required.

Common Mistakes
  • Unequal Sector Angles: Failing to accurately bisect the 9090^\circ angles into 4545^\circ angles, leading to an irregular star shape.
  • Incorrect Point Connections: Connecting adjacent points (forming an octagon) or skipping the wrong number of vertices instead of connecting each point to the third point clockwise.
  • Inverted Shading: Shading the outer star tips (AA through HH) instead of the alternating inner triangular regions.

More questions in FIO

Q1

When constructing the perpendicular bisector, is it necessary to have the same radius for the arcs above and below XYXY? Explore this through construction, and then justify your answer.

[Hint 1: Any point that is of the same distance from XX and YY lies on the perpendicular bisector.

Hint 2: We can draw the whole line if any two of its points are known.]

Q2

Is it necessary to construct the pairs of arcs above and below XYXY? Instead, can we construct both the pairs of arcs on the same side of XYXY? Explore this through construction, and then justify your answer.

Q3

While constructing one pair of intersecting arcs, is it necessary that we use the same radii for both of them ? Explore this through construction, and then justify your answer.

Q4

Recreate this design using only a ruler and compass —

Q5

Justify why AB\text{AB} in Fig. 6.4 is the perpendicular bisector.

Q6

Can you think of different methods to construct a 9090^\circ angle at a given point on a line using a rope?

Q7

Construct at least 4 different angles. Draw their bisectors.

Q8

Construct the 8-petalled figure shown in Fig. 6.5.

Q9

In Step 2 of angle bisection, if arcs of equal radius are drawn on the other side, as shown in the figure, will the line OCOC still be an angle bisector? Explore this through construction, and then justify your answer.

Q10

What are the other angles that can be constructed using angle bisection? Can you construct 65.565.5^\circ angle?

Q11

Come up with a method to construct the angle bisector using a rope.

Q12

Construct the following figure.

How do we construct the petals so that they are of the maximum possible size within a given square?

Q13

Construct at least 4 different angles in different orientations without taking any measurement. Make a copy of all these angles.

Q14

Construct the Fig. 6.6.

Q15

Construct 4 pairs of parallel lines in different orientations.

Q16

Construct the following figure.

Q17

Use support lines in Fig. 6.11 to construct a pointed arch. Make different arches, by changing the radius of the arcs.

Q18

Make your own arch designs.

Q19

Construct the following figures:

Q20

Optical Illusion: Do you notice anything interesting about the following figure? How does this happen? Recreate this in your notebook.

Q21

Construct this figure.

[Hint: Find the angles in this figure.]

Q22

Draw a line ll and mark a point PP anywhere outside the line. Construct a perpendicular to the given line ll through PP.

[Hint: Find a line segment on ll whose perpendicular bisector passes through PP.]

Q23

How can the tangram pieces be rearranged to form each of the following figures?

Q24

Are the following tilings possible?

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