Home › CBSE Class 9 › mathematics › c9sumnaturals › Per NCERT, what is the 10th triangular number us…
Per NCERT, what is the 10th triangular number using tₙ = n(n+1)/2?
A55
B45
C100
D110
Answer & Solution
Correct answer: A. 55
Per NCERT, t₁₀ = 10 × 11 / 2 = 55.
Related questions
Per NCERT, what is the sum of the first 20 natural numbers (1 + 2 + ... + 20)?Per NCERT, the sum of 2-digit numbers DIVISIBLE BY 3 (12, 15, 18, ..., 99) is which value?Per NCERT, a child arranges marbles in rows: 1 marble in row 1, 2 in row 2, 3 in row 3, ..Per NCERT, the second part of Aryabhata's verse describes Sₙ as which equivalent expressioPer NCERT, the proof of Sₙ = n(n+1)/2 uses the algebraic identity 2S = n(n+1). What is thePer NCERT, the sum 25 + 26 + 27 + ... + 58 can be computed as which expression?Per NCERT, the nth TRIANGULAR NUMBER tₙ (1, 3, 6, 10, 15, ...) equals the sum of the firstPer NCERT, the sum 1 + 2 + 3 + ... + 100 equals which value?