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Finding the Fourth Proportional to 861.06, 1,290.52 and 421.95

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Solution

The fourth proportional to 861.06, 1,290.52 and 421.95 is: 632.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.06 : 1,290.52 = 421.95 : x
  2. Step 2: Convert to fraction form
    861.06/1,290.52 = 421.95/x
  3. Step 3: Cross multiply
    861.06x = 1,290.52 × 421.95
  4. Step 4: Simplify right side
    861.06x = 544,534.91
  5. Step 5: Solve for x
    x = 544,534.91/861.06
  6. Step 6: Final answer
    x = 632.40

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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.