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Finding the Fourth Proportional to 100, 138.04 and 65.60

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Solution

The fourth proportional to 100, 138.04 and 65.60 is: 90.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    100 : 138.04 = 65.60 : x
  2. Step 2: Convert to fraction form
    100/138.04 = 65.60/x
  3. Step 3: Cross multiply
    100x = 138.04 × 65.60
  4. Step 4: Simplify right side
    100x = 9,055.42
  5. Step 5: Solve for x
    x = 9,055.42/100
  6. Step 6: Final answer
    x = 90.55

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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.