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Finding the Fourth Proportional to 1,420.95, 2,129.90 and 641.37

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Solution

The fourth proportional to 1,420.95, 2,129.90 and 641.37 is: 961.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.95 : 2,129.90 = 641.37 : x
  2. Step 2: Convert to fraction form
    1,420.95/2,129.90 = 641.37/x
  3. Step 3: Cross multiply
    1,420.95x = 2,129.90 × 641.37
  4. Step 4: Simplify right side
    1,420.95x = 1,366,050.76
  5. Step 5: Solve for x
    x = 1,366,050.76/1,420.95
  6. Step 6: Final answer
    x = 961.36

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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.