Does anyone know how he got from step one to step two?

Aplot of land is shaped like a quadrilateral. fences are built on the diagonal to divide the area into 4 sections. what is vi to the nearest tenth? gv = 6.55fv = 5.84vh = 3.27vi = ?

The areas of two similar triangles are 72dm2 and 50dm2. the sum of their perimeters is 226dm. what is the perimeter of each of these triangles?

Acomposition of transformations maps δxyz to δx"y"z". the first transformation for this composition is , and the second transformation is a 90° rotation about point x'.