How do you calculate wavelength and frequency?

Asap! how do you lengthen a pattern piece? (family and consumer science, sewing)

According to the vsepr theory what is the shape of a molecule that has a central atom valence three other items with no lone pairs of electrons

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.