I hope this helps!
Square perimeter formula: P = 4a
Rectangle perimeter formula: P = 2(a + b)
Triangle perimeter formulas:
P = a + b + c or
P = a + b + √(a² + b² - 2ab * cos(γ)) or
P = a + (a / sin(β + γ)) * (sin(β) + sin(γ))
Circle perimeter formula: P = 2πr
Circle sector perimeter formula: P = r(α + 2) (α is in radians)
Ellipse perimeter formula: P = π(3(a + b) - √((3a + b) * (a + 3b)))
Quadrilateral / Trapezoid perimeter formula: P = a + b + c + d
Parallelogram perimeter formulas:
P = 2(a + b) or
P = 2a² + √(2e² + 2f² - 4a²) or
P = 2(b + h/sin(α))
Rhombus perimeter formulas:
P = 4a or
P = 2√(e² + f²)
Kite perimeter formula: P = 2(a + b)
Annulus perimeter formula: P = 2π(R + r)
Regular polygon area formula: P = n * a