per+ areas

• perimeter: length around

  Area: inside
• A of square/ rectangle: LxB

  P of square: add all 4 sides or Lx4
• p of rectangle: add all 4 sides or Lx2+Bx2 or (L+B)x2
• area of triangle: basexheight divided by 2

  perimeter: add all 3 sides
• A of parallelogram: base x perpendicular height

  P of parallelogram: add all 3 sides
• A of rhombus: product of diagonals divided by 2

  P of rhombus: add sides