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Finding the Fourth Proportional to 813.60, 1,218.24 and 428.04

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Solution

The fourth proportional to 813.60, 1,218.24 and 428.04 is: 640.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.60 : 1,218.24 = 428.04 : x
  2. Step 2: Convert to fraction form
    813.60/1,218.24 = 428.04/x
  3. Step 3: Cross multiply
    813.60x = 1,218.24 × 428.04
  4. Step 4: Simplify right side
    813.60x = 521,455.45
  5. Step 5: Solve for x
    x = 521,455.45/813.60
  6. Step 6: Final answer
    x = 640.92

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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.