Theperimeterofarectangularplotoflandis250meterr.Ifthelengthofonesideoftheplotis40meters,whatistheareaoftheplot,insuqremeters.
Naomimakessilverjewelry.Foronestyleofearrings,shecutswedgesfromasilverdisk,asshowninthefigureabove.Eachwedgemakesa40°angleatthecenterofthedisk.Iftheweightofeachuncutdiskisaunidormlydistributed2.5grams,howmanygramsdoeseachwedgeweigh.
这两题有点看不懂,