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Finding the Fourth Proportional to 691.32, 954.70 and 642.18

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Solution

The fourth proportional to 691.32, 954.70 and 642.18 is: 886.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.32 : 954.70 = 642.18 : x
  2. Step 2: Convert to fraction form
    691.32/954.70 = 642.18/x
  3. Step 3: Cross multiply
    691.32x = 954.70 × 642.18
  4. Step 4: Simplify right side
    691.32x = 613,089.25
  5. Step 5: Solve for x
    x = 613,089.25/691.32
  6. Step 6: Final answer
    x = 886.84

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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.