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Finding the Fourth Proportional to 612.66, 916.95 and 438.78

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Solution

The fourth proportional to 612.66, 916.95 and 438.78 is: 656.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.66 : 916.95 = 438.78 : x
  2. Step 2: Convert to fraction form
    612.66/916.95 = 438.78/x
  3. Step 3: Cross multiply
    612.66x = 916.95 × 438.78
  4. Step 4: Simplify right side
    612.66x = 402,339.32
  5. Step 5: Solve for x
    x = 402,339.32/612.66
  6. Step 6: Final answer
    x = 656.71

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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.