The scale rates the strength of earthquake as a magnitude

The "Richter Scale" rates the strength of earthquake as a magnitude

Hope this helps!

A,) cause a & b are equal & both gives 180°

The us is first  the  u.s. economy  remains the  largest in the world  in terms of nominal  gdp. however, the  u.s. economy  loses its spot as the number one  economy  to china when  measured  in terms of  gdp  based on ppp. in these terms, china's  gdp  is $23.19 trillion exceeds the  u.s. gdp  of $19.42 trillion