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Finding the Fourth Proportional to 1,421.08, 2,129.96 and 641.48

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Solution

The fourth proportional to 1,421.08, 2,129.96 and 641.48 is: 961.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,421.08 : 2,129.96 = 641.48 : x
  2. Step 2: Convert to fraction form
    1,421.08/2,129.96 = 641.48/x
  3. Step 3: Cross multiply
    1,421.08x = 2,129.96 × 641.48
  4. Step 4: Simplify right side
    1,421.08x = 1,366,317.69
  5. Step 5: Solve for x
    x = 1,366,317.69/1,421.08
  6. Step 6: Final answer
    x = 961.47

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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.