79.3 millimeters of rain ^ 151.19 metres squared

Are you asking how much water that will be over 151.19m²  ?

It is probably best to put them both in cm

 

79.3mm=79.3/10 = 7.93cm

 

100*100=10,000cm² in a m²

151.19 * 10,000 = 1,511,900 cm²

 

$${\mathtt{1\,511\,900}}{\mathtt{\,\times\,}}{\mathtt{7.93}} = {\mathtt{11\,989\,367}}$$ cm³   =  11,989,367ml =  11,989.367 Litres

 

so that is 11,989 Litres which is almost 12Kilolitres