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Finding the Fourth Proportional to 312, 432.40 and 307.20

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Solution

The fourth proportional to 312, 432.40 and 307.20 is: 425.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    312 : 432.40 = 307.20 : x
  2. Step 2: Convert to fraction form
    312/432.40 = 307.20/x
  3. Step 3: Cross multiply
    312x = 432.40 × 307.20
  4. Step 4: Simplify right side
    312x = 132,833.28
  5. Step 5: Solve for x
    x = 132,833.28/312
  6. Step 6: Final answer
    x = 425.75

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.