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Finding the Fourth Proportional to 762.80, 1,145.40 and 438.80

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Solution

The fourth proportional to 762.80, 1,145.40 and 438.80 is: 658.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    762.80 : 1,145.40 = 438.80 : x
  2. Step 2: Convert to fraction form
    762.80/1,145.40 = 438.80/x
  3. Step 3: Cross multiply
    762.80x = 1,145.40 × 438.80
  4. Step 4: Simplify right side
    762.80x = 502,601.52
  5. Step 5: Solve for x
    x = 502,601.52/762.80
  6. Step 6: Final answer
    x = 658.89

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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.