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Finding the Fourth Proportional to 689.64, 951.69 and 390.88

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Solution

The fourth proportional to 689.64, 951.69 and 390.88 is: 539.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.64 : 951.69 = 390.88 : x
  2. Step 2: Convert to fraction form
    689.64/951.69 = 390.88/x
  3. Step 3: Cross multiply
    689.64x = 951.69 × 390.88
  4. Step 4: Simplify right side
    689.64x = 371,999.24
  5. Step 5: Solve for x
    x = 371,999.24/689.64
  6. Step 6: Final answer
    x = 539.41

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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.