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Finding the Fourth Proportional to 806.10, 1,209.16 and 421.30

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Solution

The fourth proportional to 806.10, 1,209.16 and 421.30 is: 631.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.10 : 1,209.16 = 421.30 : x
  2. Step 2: Convert to fraction form
    806.10/1,209.16 = 421.30/x
  3. Step 3: Cross multiply
    806.10x = 1,209.16 × 421.30
  4. Step 4: Simplify right side
    806.10x = 509,419.11
  5. Step 5: Solve for x
    x = 509,419.11/806.10
  6. Step 6: Final answer
    x = 631.96

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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.