The length of the base is b ≤ 11.1 cm.
Solution:
Height of the triangle = 90 cm
Area of the triangle is at most 500 cm²
Area of the triangle ≤ 500
[tex]$\frac{1}{2}\times \text{base}\times\text{height} \leq 500[/tex]
[tex]$\frac{1}{2}\times b\times 90 \leq 500[/tex]
b × 45 ≤ 500
Divide by 45 on both sides.
[tex]$\frac{b \times 45}{45}\leq \frac{500}{45}[/tex]
b ≤ 11.11111111 cm
b ≤ 11.1 cm
The length of the base is b ≤ 11.1 cm.