The distance from the point (x₀,y₀) to the line ax+by+c=0 is |ax₀ + by₀ + c| / √(a² + b²)
This radius is |3(-4) + 4(-2) - 5| / √(3² + 4²) which simplifies to 5.
The line perpendicular to ax+by+c through a given point (x₀,y₀) is bx-ay-(bx₀-ay₀)=0.
The equation of the diameter perpendicular to 3x+4y-5=0 is 4x-3y-(4(-4)-3(-2))=0 which simplifies to 4x-3y-10=0
Graph:
https://www.desmos.com/calculator/rvwuqvds6o