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Finding the Fourth Proportional to 287.10, 430.65 and 261.90

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Solution

The fourth proportional to 287.10, 430.65 and 261.90 is: 392.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.10 : 430.65 = 261.90 : x
  2. Step 2: Convert to fraction form
    287.10/430.65 = 261.90/x
  3. Step 3: Cross multiply
    287.10x = 430.65 × 261.90
  4. Step 4: Simplify right side
    287.10x = 112,787.24
  5. Step 5: Solve for x
    x = 112,787.24/287.10
  6. Step 6: Final answer
    x = 392.85

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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.