Problem 35

To determine whether a set of three numbers can form a right-angled triangle, we use the Pythagorean theorem, which states that in a right-angled triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides.

For each set of numbers:

A: $3^2 + 4^2 = 5^2$
Calculating each term gives $9 + 16 = 25$, which holds true.
Therefore, option A can form a right-angled triangle.

B: $6^2 + 8^2 \not= 11^2$
Calculating each term gives $36 + 64 \not= 121$.
Since the equation does not hold true, option B cannot form a right-angled triangle.

C: $8^2 + 15^2 = 17^2$
Calculating each term gives $64 + 225 = 289$, which holds true.
Therefore, option C can form a right-angled triangle.

D: $7^2 + 24^2 = 25^2$
Calculating each term gives $49 + 576 = 625$, which holds true.
Therefore, option D can form a right-angled triangle.

Since the problem asks for the set of numbers that cannot form a right-angled triangle, the correct answer is:
$$\boxed{B: 6, 8, 11}$$