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Finding the Fourth Proportional to 78.18, 117.21 and 29.40

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Solution

The fourth proportional to 78.18, 117.21 and 29.40 is: 44.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.18 : 117.21 = 29.40 : x
  2. Step 2: Convert to fraction form
    78.18/117.21 = 29.40/x
  3. Step 3: Cross multiply
    78.18x = 117.21 × 29.40
  4. Step 4: Simplify right side
    78.18x = 3,445.97
  5. Step 5: Solve for x
    x = 3,445.97/78.18
  6. Step 6: Final answer
    x = 44.08

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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.