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Finding the Fourth Proportional to 1,291.70, 1,937.80 and 511.55

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Solution

The fourth proportional to 1,291.70, 1,937.80 and 511.55 is: 767.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,291.70 : 1,937.80 = 511.55 : x
  2. Step 2: Convert to fraction form
    1,291.70/1,937.80 = 511.55/x
  3. Step 3: Cross multiply
    1,291.70x = 1,937.80 × 511.55
  4. Step 4: Simplify right side
    1,291.70x = 991,288.16
  5. Step 5: Solve for x
    x = 991,288.16/1,291.70
  6. Step 6: Final answer
    x = 767.43

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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.