2. Among the triangles with side lengths being consecutive natural numbers and a perimeter not exceeding 100, the number of acute triangles is $\qquad$
$(1987$, National Junior High School Mathematics League)
提示: Set the three sides of the triangle to be $n-1$, $n$, and $n+1$. When $n>24$, $(n-1)^{2}+n^{2}>(n+1)^{2}$, so the triangle is an acute triangle. Therefore, the number of acute triangles that meet the requirements is 29.