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Finding the Fourth Proportional to 155.61, 214.74 and 100.40

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Solution

The fourth proportional to 155.61, 214.74 and 100.40 is: 138.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.61 : 214.74 = 100.40 : x
  2. Step 2: Convert to fraction form
    155.61/214.74 = 100.40/x
  3. Step 3: Cross multiply
    155.61x = 214.74 × 100.40
  4. Step 4: Simplify right side
    155.61x = 21,558.82
  5. Step 5: Solve for x
    x = 21,558.82/155.61
  6. Step 6: Final answer
    x = 138.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.