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Finding the Fourth Proportional to 611.76, 916.56 and 420.24

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Solution

The fourth proportional to 611.76, 916.56 and 420.24 is: 629.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.76 : 916.56 = 420.24 : x
  2. Step 2: Convert to fraction form
    611.76/916.56 = 420.24/x
  3. Step 3: Cross multiply
    611.76x = 916.56 × 420.24
  4. Step 4: Simplify right side
    611.76x = 385,175.17
  5. Step 5: Solve for x
    x = 385,175.17/611.76
  6. Step 6: Final answer
    x = 629.62

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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.