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Finding the Fourth Proportional to 810.91, 1,214.43 and 419.86

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Solution

The fourth proportional to 810.91, 1,214.43 and 419.86 is: 628.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.91 : 1,214.43 = 419.86 : x
  2. Step 2: Convert to fraction form
    810.91/1,214.43 = 419.86/x
  3. Step 3: Cross multiply
    810.91x = 1,214.43 × 419.86
  4. Step 4: Simplify right side
    810.91x = 509,890.58
  5. Step 5: Solve for x
    x = 509,890.58/810.91
  6. Step 6: Final answer
    x = 628.79

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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.