circle.rb

class Circle

	attr_reader :radius

	def initialize(radius)
		@radius = radius
	end

	def diameter
		@radius * 2
	end

	def circumference
		(@radius * 2 * (Math::PI)).round(2)
	end

	def area
		((@radius ** 2) * (Math::PI)).round(2)
	end

end

circle_spec.rb

require_relative '../../lib/circle'

describe Circle do

	let(:circle) { Circle.new(5.0) }

	it 'should have a radius' do
		expect(circle.radius).to eql 5.0
	end

	it 'calculates the diameter' do
		expect(circle.diameter).to eql 10.0
	end

	it 'calculates the circumference' do
		expect(circle.circumference).to eql 31.42
	end

	it 'calculates the area' do
		expect(circle.area).to eql 78.54
	end
end

rectangle.rb

class Rectangle

	attr_reader :length, :height

	def initialize(length, height)
		@length = length.to_f
		@height = height.to_f
	end

	def perimeter
		(@length * 2) + (@height * 2)
	end

	def area
		@length * @height
	end

end

rectangle_spec.rb

require 'rspec'
require_relative '../../lib/rectangle'

describe Rectangle do
	let(:rectangle) { Rectangle.new(10,5) }

	it 'should have a length' do
		expect(rectangle.length).to eql 10.0
	end

	it 'should have a height' do
		expect(rectangle.height).to eql 5.0
	end

	it 'calculates the perimeter' do
		expect(rectangle.perimeter).to eql 30.0
	end

	it 'calculates the area' do
		expect(rectangle.area).to eql 50.0
	end

end

square.rb

class Square

	attr_reader :side

	def initialize(side)
		@side = side.to_f
	end

	def perimeter
		@side * 4
	end

	def area
		@side ** 2
	end
end

square_spec.rb

require 'rspec'
require_relative '../../lib/square'

describe Square do

	let(:square) { Square.new(10.0) }

	it 'should have a side' do
		expect(square.side).to eql 10.0
	end

	it 'calculates the perimeter' do
		expect(square.perimeter).to eql 40.0 
	end

	it 'calculates the area' do
		expect(square.area).to eql 100.0
	end
end

trapezoid.rb

class Trapezoid

	attr_reader :a, :b, :c, :d, :height

	def initialize(bottom_base,top_base,left_side,right_side,height)
		@a = bottom_base.to_f
		@b = top_base.to_f
		@c = left_side.to_f
		@d = right_side.to_f
		@height = height.to_f
	end

	def perimeter
		@a + @b + @c + @d
	end

	def area
		0.5 * (@a+@b) * @height
	end

end

trapezoid_spec.rb

require 'rspec'
require_relative '../../lib/trapezoid'

describe Trapezoid do
	let(:trapezoid) { Trapezoid.new(289,25,129,135,129) }

	it 'should have a bottom base' do
		expect(trapezoid.a).to eql(289.0)
	end

	it 'should have a top base' do
		expect(trapezoid.b).to eql(25.0)
	end

	it 'should have a left side' do
		expect(trapezoid.c).to eql(129.0)
	end

	it 'should have a right side' do
		expect(trapezoid.d).to eql(135.0)
	end

	it 'should have a height' do
		expect(trapezoid.height).to eql(129.0)
	end

	it 'calculates the perimeter' do
		expect(trapezoid.perimeter).to eql(578.0)
	end

	it 'calculates the area' do
		expect(trapezoid.area).to eql (20253.0)
	end
end

triangle.rb

class Triangle

	attr_reader :a, :b, :c

	def initialize(a,b,c)
		@a = a.to_f
		@b = b.to_f
		@c = c.to_f
	end

	def perimeter
		@a +@b + @c
	end

	def half_perimeter
		perimeter/2
	end

	def area
		Math.sqrt(half_perimeter*(half_perimeter-@a)*(half_perimeter-@b)*(half_perimeter-@c)).round(2)
	end
	
end

triangle_spec.rb

require_relative '../../lib/triangle'

describe Triangle do
	let(:triangle) { Triangle.new(5,5,5) }

	it 'should have an a side' do 
		expect(triangle.a).to eql(5.0)
	end

	it 'should have an b side' do 
		expect(triangle.b).to eql(5.0)
	end

	it 'should have an b side' do 
		expect(triangle.c).to eql(5.0)
	end

	it 'calculates an perimeter' do
		expect(triangle.perimeter).to eql(15.0)
	end

	it 'calculates an area' do
		expect(triangle.area).to eql(10.83)
	end
end