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Finding the Fourth Proportional to 305.28, 421.20 and 207

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Solution

The fourth proportional to 305.28, 421.20 and 207 is: 285.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.28 : 421.20 = 207 : x
  2. Step 2: Convert to fraction form
    305.28/421.20 = 207/x
  3. Step 3: Cross multiply
    305.28x = 421.20 × 207
  4. Step 4: Simplify right side
    305.28x = 87,188.40
  5. Step 5: Solve for x
    x = 87,188.40/305.28
  6. Step 6: Final answer
    x = 285.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.