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Finding the Fourth Proportional to 758.40, 1,135.79 and 428.52

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Solution

The fourth proportional to 758.40, 1,135.79 and 428.52 is: 641.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    758.40 : 1,135.79 = 428.52 : x
  2. Step 2: Convert to fraction form
    758.40/1,135.79 = 428.52/x
  3. Step 3: Cross multiply
    758.40x = 1,135.79 × 428.52
  4. Step 4: Simplify right side
    758.40x = 486,712.45
  5. Step 5: Solve for x
    x = 486,712.45/758.40
  6. Step 6: Final answer
    x = 641.77

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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.