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Finding the Fourth Proportional to 821.79, 1,230.29 and 430.86

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Solution

The fourth proportional to 821.79, 1,230.29 and 430.86 is: 645.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.79 : 1,230.29 = 430.86 : x
  2. Step 2: Convert to fraction form
    821.79/1,230.29 = 430.86/x
  3. Step 3: Cross multiply
    821.79x = 1,230.29 × 430.86
  4. Step 4: Simplify right side
    821.79x = 530,088.44
  5. Step 5: Solve for x
    x = 530,088.44/821.79
  6. Step 6: Final answer
    x = 645.04

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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.