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Finding the Fourth Proportional to 720.20, 1,078.56 and 411.11

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Solution

The fourth proportional to 720.20, 1,078.56 and 411.11 is: 615.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.20 : 1,078.56 = 411.11 : x
  2. Step 2: Convert to fraction form
    720.20/1,078.56 = 411.11/x
  3. Step 3: Cross multiply
    720.20x = 1,078.56 × 411.11
  4. Step 4: Simplify right side
    720.20x = 443,406.80
  5. Step 5: Solve for x
    x = 443,406.80/720.20
  6. Step 6: Final answer
    x = 615.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.