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Finding the Fourth Proportional to 920.12, 1,269.59 and 521.78

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Solution

The fourth proportional to 920.12, 1,269.59 and 521.78 is: 719.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.12 : 1,269.59 = 521.78 : x
  2. Step 2: Convert to fraction form
    920.12/1,269.59 = 521.78/x
  3. Step 3: Cross multiply
    920.12x = 1,269.59 × 521.78
  4. Step 4: Simplify right side
    920.12x = 662,437.71
  5. Step 5: Solve for x
    x = 662,437.71/920.12
  6. Step 6: Final answer
    x = 719.95

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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.