Question

which are the possible side lengths of a triangle?
○ 3 cm, 5 cm, 9 cm
○ 4 cm, 8 cm, 10 cm
○ 6 cm, 9 cm, 17 cm
○ 8 cm, 10 cm, 18 cm

Explanation:

Step1: Apply triangle inequality theorem

Sum of two sides > third side.

Step2: Check first option

$3+5=8 < 9$ → invalid.

Step3: Check second option

$4+8=12 >10$, $4+10=14>8$, $8+10=18>4$ → valid.

Step4: Check third option

$6+9=15 <17$ → invalid.

Step5: Check fourth option

$8+10=18$ (not >18) → invalid.

Answer:

B. 4 cm, 8 cm, 10 cm