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Finding the Fourth Proportional to 820.89, 1,231.35 and 457.99

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Solution

The fourth proportional to 820.89, 1,231.35 and 457.99 is: 686.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.89 : 1,231.35 = 457.99 : x
  2. Step 2: Convert to fraction form
    820.89/1,231.35 = 457.99/x
  3. Step 3: Cross multiply
    820.89x = 1,231.35 × 457.99
  4. Step 4: Simplify right side
    820.89x = 563,941.19
  5. Step 5: Solve for x
    x = 563,941.19/820.89
  6. Step 6: Final answer
    x = 686.99

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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.