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Lesson 6-3: Real-World Applications

City Planning Challenge

Learning Objectives

By the end of this lesson, you will:

  • Apply math concepts to authentic real-world situations
  • Make informed decisions using mathematical reasoning
  • Use critical thinking to evaluate solutions
  • Communicate mathematical ideas clearly

Real-World Skills:

Decision MakingCritical ThinkingProblem AnalysisSolution EvaluationCommunicationPractical Application

City Planning Challenge

You're part of a team planning a new neighborhood in your city. This involves making important decisions about land use, infrastructure, and community services. You'll need to use all your math skills to analyze data, calculate costs, and make recommendations that will affect thousands of people.

Land Development

Calculate areas, costs, and optimal layouts for different land uses

Infrastructure Planning

Design roads, utilities, and services using geometric calculations

Community Services

Analyze population data and plan schools, parks, and facilities

Problem 1: Land Use Planning

The Challenge:

You have 120 acres of land to develop. City regulations require: 40% residential, 25% commercial, 20% parks, and 15% roads/utilities. Residential land sells for $50,000 per acre, commercial for $80,000 per acre. Parks cost $15,000 per acre to develop. What's the total revenue and cost for this development?

Step 1: Calculate Land Allocation (Fractions & Decimals)

Determine how many acres go to each land use type.

Residential: 120 × 0.40 = 48 acres
Commercial: 120 × 0.25 = 30 acres
Parks: 120 × 0.20 = 24 acres
Roads/Utilities: 120 × 0.15 = 18 acres

Step 2: Calculate Revenue (Decimals)

Find revenue from selling residential and commercial land.

Residential revenue = 48 × $50,000 = $2,400,000
Commercial revenue = 30 × $80,000 = $2,400,000
Total revenue = $2,400,000 + $2,400,000 = $4,800,000

Step 3: Calculate Development Costs (Decimals)

Find the cost to develop parks and infrastructure.

Park development cost = 24 × $15,000 = $360,000
Road/utility cost = 18 × $25,000 = $450,000
Total development cost = $360,000 + $450,000 = $810,000

Step 4: Calculate Net Profit

Find the net profit after subtracting development costs.

Net profit = $4,800,000 - $810,000 = $3,990,000

Answer:

Total revenue: $4,800,000
Development cost: $810,000
Net profit: $3,990,000

Problem 2: Infrastructure Design

The Challenge:

You need to design a road network connecting all areas. The main road is 2.5 miles long and 40 feet wide. Side roads are 1.2 miles long and 24 feet wide. If asphalt costs $85 per square yard, and 1 mile = 1,760 yards, what's the total cost for paving all roads?

Step 1: Convert Measurements (Decimals)

Convert all measurements to yards for consistent units.

Main road: 2.5 miles × 1,760 yards/mile = 4,400 yards long
Main road width: 40 feet ÷ 3 feet/yard = 13.33 yards wide
Side roads: 1.2 miles × 1,760 yards/mile = 2,112 yards long
Side road width: 24 feet ÷ 3 feet/yard = 8 yards wide

Step 2: Calculate Road Areas (Geometry)

Find the area of each type of road.

Main road area = 4,400 × 13.33 = 58,652 square yards
Side road area = 2,112 × 8 = 16,896 square yards
Total road area = 58,652 + 16,896 = 75,548 square yards

Step 3: Calculate Paving Cost (Decimals)

Find the total cost to pave all roads.

Total paving cost = 75,548 × $85 = $6,421,580

Answer:

The total cost for paving all roads is $6,421,580.

Problem 3: Community Services Analysis

The Challenge:

The new neighborhood will have 1,200 families. City standards require: 1 school per 400 families, 1 park per 300 families, and 1 library per 600 families. Each school costs $8.5 million, each park costs $2.3 million, and each library costs $4.7 million. What's the total cost for community services?

Step 1: Calculate Number of Facilities Needed (Algebra)

Determine how many of each type of facility are needed.

Schools needed = 1,200 ÷ 400 = 3 schools
Parks needed = 1,200 ÷ 300 = 4 parks
Libraries needed = 1,200 ÷ 600 = 2 libraries

Step 2: Calculate Individual Costs (Decimals)

Find the cost for each type of facility.

School cost = 3 × $8,500,000 = $25,500,000
Park cost = 4 × $2,300,000 = $9,200,000
Library cost = 2 × $4,700,000 = $9,400,000

Step 3: Calculate Total Cost

Add up all facility costs.

Total cost = $25,500,000 + $9,200,000 + $9,400,000 = $44,100,000

Step 4: Calculate Cost per Family

Find the average cost per family for community services.

Cost per family = $44,100,000 ÷ 1,200 families = $36,750 per family

Answer:

Total cost for community services: $44,100,000
Cost per family: $36,750

Real-World Decision Making Framework

Problem Analysis

  • • Identify all relevant factors and constraints
  • • Gather and organize necessary data
  • • Consider multiple perspectives and stakeholders

Mathematical Modeling

  • • Translate real situations into mathematical problems
  • • Choose appropriate mathematical tools and concepts
  • • Apply multiple strategies when needed

Solution Evaluation

  • • Check if solutions are reasonable and practical
  • • Consider alternative approaches and solutions
  • • Evaluate trade-offs and consequences

Communication

  • • Present findings clearly and logically
  • • Explain mathematical reasoning in accessible terms
  • • Support recommendations with evidence

Practice Problems

Practice 1: Environmental Impact

A new development will remove 3/8 of a 240-acre forest. The remaining forest can absorb 0.4 tons of CO₂ per acre per year. If the city produces 1,200 tons of CO₂ per year, what percentage of the city's CO₂ can the remaining forest absorb?

Real-world context: Environmental planning and carbon footprint analysis

Practice 2: Emergency Services

A fire station needs to serve a 5-mile radius. The new neighborhood is 3.2 miles from the nearest station. If response time is 1.5 minutes per mile, and the maximum acceptable response time is 8 minutes, do you need a new fire station?

Real-world context: Public safety and emergency response planning

Practice 3: Economic Impact

The new development will create 450 jobs. Each job generates $2,800 in monthly spending. If 60% of this spending stays in the local economy, and the local economy has a multiplier effect of 1.4, what's the total monthly economic impact?

Real-world context: Economic development and community impact analysis

Congratulations! You've Completed 5th Grade Math!

You've successfully applied all the math concepts you've learned throughout 5th grade to solve complex, real-world problems. You now have the skills to:

Mathematical Skills

  • • Work with fractions, decimals, and percentages
  • • Solve algebraic equations and inequalities
  • • Calculate areas, volumes, and surface areas
  • • Analyze data and calculate probabilities

Problem-Solving Skills

  • • Break down complex problems into steps
  • • Integrate multiple math concepts
  • • Apply math to real-world situations
  • • Make informed decisions using data

Amazing Achievement!

You've mastered all the essential 5th grade math concepts and can now apply them to solve real-world problems. You're ready for 6th grade math and beyond!