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Finding the Fourth Proportional to 1,421.49, 2,132.92 and 642.05

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Solution

The fourth proportional to 1,421.49, 2,132.92 and 642.05 is: 963.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,421.49 : 2,132.92 = 642.05 : x
  2. Step 2: Convert to fraction form
    1,421.49/2,132.92 = 642.05/x
  3. Step 3: Cross multiply
    1,421.49x = 2,132.92 × 642.05
  4. Step 4: Simplify right side
    1,421.49x = 1,369,430.62
  5. Step 5: Solve for x
    x = 1,369,430.62/1,421.49
  6. Step 6: Final answer
    x = 963.38

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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.