What percentage of the total length of side and rear property lines on which a firewall may be constructed on R-3 zoned properties?

The correct answer, which is 90%, reflects the specific regulations set forth in zoning laws pertaining to R-3 zoned properties. In this context, a firewall is typically required for buildings that are situated in proximity to property lines to prevent fire from spreading between structures, especially in densely populated areas or multi-family housing situations.

The 90% figure indicates a significant allowance for the potential construction of firewalls along the edges of properties. This percentage is likely grounded in safety regulations that aim to ensure adequate protection for adjacent buildings while maximizing the usable space of the property in compliance with building codes. Such regulations are tailored to maintain fire safety standards while also addressing the practical realities of land use in residential developments.

Other options present smaller percentages that would not sufficiently address the fire safety concerns inherent in R-3 zoned areas, where high-density housing is common. The choice of 90% thus strikes a balance between regulatory safety requirements and practical development needs.