clear
//Given
h=300
R=6.4*10**6                       //m
N=10**12

//Calculation
//
d=sqrt(2*R*h)
fc=9*N**0.5

//Result
printf("\n fc= %0.3f  MHz", fc*10**-6)
printf("\n 5 MHz comes via ionospheric propogation.and 100 MHz signal comes via satellite transmission.")