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Finding the Fourth Proportional to 813.66, 1,221.03 and 429.18

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Solution

The fourth proportional to 813.66, 1,221.03 and 429.18 is: 644.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.66 : 1,221.03 = 429.18 : x
  2. Step 2: Convert to fraction form
    813.66/1,221.03 = 429.18/x
  3. Step 3: Cross multiply
    813.66x = 1,221.03 × 429.18
  4. Step 4: Simplify right side
    813.66x = 524,041.66
  5. Step 5: Solve for x
    x = 524,041.66/813.66
  6. Step 6: Final answer
    x = 644.05

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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.