Visual reasoning

PYQ (2022 paper)

• 2022 · G4 · Question 172 · Final answer key

Free questions

1. Question 1

   In a square, the midpoints of the four sides are joined in order (a rhombus), and the two midlines joining the midpoints of opposite sides are drawn. How many triangles are there in this figure?

   1. A. 8
   2. B. 12
   3. C. 16
   4. D. 4
   Answer and explanation

   ✓ Correct answer: B. 12

   4 triangles at the corners outside the rhombus; the midlines cut the rhombus into 4 small triangles; 4 more triangles each made of two neighbouring small ones; 4 + 4 + 4 = 12 (a systematic list of vertices also gives 12).

   Source: கணக்கு, ஆறாம் வகுப்பு, முதல் பருவம், தொகுதி 2, தமிழ் வழி (Mathematics, Standard VI, Term I, Volume 2, Tamil medium; Samacheer Kalvi) (இயல் 6 தகவல் செயலாக்கம் (பயிற்சி 6.1), p. 118 (PDF p. 122))

2. Question 2

   The midpoints of the three sides of a triangle are joined by straight lines. How many triangles are there in this figure altogether?

   1. A. 5
   2. B. 4
   3. C. 6
   4. D. 8
   Answer and explanation

   ✓ Correct answer: A. 5

   Joining the midpoints gives 4 small triangles; two or three of them together do not form a triangle; all four together form the big one; 4 + 1 = 5 in all.

   Source: கணக்கு, ஆறாம் வகுப்பு, முதல் பருவம், தொகுதி 2, தமிழ் வழி (Mathematics, Standard VI, Term I, Volume 2, Tamil medium; Samacheer Kalvi) (இயல் 6 தகவல் செயலாக்கம் (6.3.3 படத்திற்குள் பல படங்கள்), p. 117 (PDF p. 121))

3. Question 3

   A five-pointed star is drawn with five straight lines. How many small triangles are there at its points?

   1. A. 10
   2. B. 3
   3. C. 5
   4. D. 6
   Answer and explanation

   ✓ Correct answer: C. 5

   Each point is a small triangle; with five points there are 5 small triangles (a pentagon is left in the middle).

   Source: கணக்கு, ஆறாம் வகுப்பு, முதல் பருவம், தொகுதி 2, தமிழ் வழி (Mathematics, Standard VI, Term I, Volume 2, Tamil medium; Samacheer Kalvi) (இயல் 6 தகவல் செயலாக்கம் (6.3.3 படத்திற்குள் பல படங்கள்), p. 117 (PDF p. 121))