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Finding the Fourth Proportional to 313.60, 470.40 and 85.60

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Solution

The fourth proportional to 313.60, 470.40 and 85.60 is: 128.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    313.60 : 470.40 = 85.60 : x
  2. Step 2: Convert to fraction form
    313.60/470.40 = 85.60/x
  3. Step 3: Cross multiply
    313.60x = 470.40 × 85.60
  4. Step 4: Simplify right side
    313.60x = 40,266.24
  5. Step 5: Solve for x
    x = 40,266.24/313.60
  6. Step 6: Final answer
    x = 128.40

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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.