Mushy-Pea Mystery

This week there was a terrible crime in Voyager 6.  Mr Shammas's entire annual supply of mushy peas was stolen, and all that were left behind were footprints and handprints of green goo.  They were somewhat larger than one might expect.

Luckily, his maths class were on hand to assist in the solving of this murky mystery.  Here they are using their best measuring, averaging and scaling skills...