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Finding the Fourth Proportional to 520.71, 780.91 and 429.18

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Solution

The fourth proportional to 520.71, 780.91 and 429.18 is: 643.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.71 : 780.91 = 429.18 : x
  2. Step 2: Convert to fraction form
    520.71/780.91 = 429.18/x
  3. Step 3: Cross multiply
    520.71x = 780.91 × 429.18
  4. Step 4: Simplify right side
    520.71x = 335,153.76
  5. Step 5: Solve for x
    x = 335,153.76/520.71
  6. Step 6: Final answer
    x = 643.65

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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.