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Finding the Fourth Proportional to 309.72, 427.08 and 284.40

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Solution

The fourth proportional to 309.72, 427.08 and 284.40 is: 392.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.72 : 427.08 = 284.40 : x
  2. Step 2: Convert to fraction form
    309.72/427.08 = 284.40/x
  3. Step 3: Cross multiply
    309.72x = 427.08 × 284.40
  4. Step 4: Simplify right side
    309.72x = 121,461.55
  5. Step 5: Solve for x
    x = 121,461.55/309.72
  6. Step 6: Final answer
    x = 392.17

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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.