Class 10 Geometric Patterns — practice questions with answers
Algebra — Sequences · 5 sample questions from the school syllabus. Try each one, then open the answer and the worked solution.
1. Find the next term in the pattern: 2, 6, 18, 54, ...
A108
B162
C126
D216
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Answer: B) 162
Each term is multiplied by 3 (common ratio = 3). So next term = 54 x 3 = 162.
2. Which term of the pattern 2, 6, 18, 54, ... has the value 486?
A5th
B6th
C7th
D4th
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Answer: B) 6th
a r^(n-1) = 2 x 3^(n-1) = 486 gives 3^(n-1) = 243 = 3⁵, so n - 1 = 5, n = 6.
3. What is the 7th term of the pattern 1, 2, 4, 8, ...?
A32
B64
C128
D256
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Answer: B) 64
7th term = 2^(7-1) = 2⁶ = 64.
4. A geometric pattern has 3rd term 20 and 5th term 80. Given all terms are positive, find the common ratio.
A2
B4
C1.5
D3
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Answer: A) 2
5th/3rd = r² = 2080 = 4, so r = 2 (positive terms).
5. A geometric pattern of triangle perimeters is 48, 24, 12, ... cm, where each triangle's perimeter is half the previous one. The pattern continues forever. What is the sum of all the perimeters (48 + 24 + 12 + ...)?
A96 cm
B120 cm
C144 cm
Dinfinite
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Answer: A) 96 cm
Infinite sum of a geometric pattern with first term 48 and ratio 21 = 1−ra=1−2148=2148 = 96 cm.