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Finding the Fourth Proportional to 78.56, 117.80 and 38

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Solution

The fourth proportional to 78.56, 117.80 and 38 is: 56.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.56 : 117.80 = 38 : x
  2. Step 2: Convert to fraction form
    78.56/117.80 = 38/x
  3. Step 3: Cross multiply
    78.56x = 117.80 × 38
  4. Step 4: Simplify right side
    78.56x = 4,476.40
  5. Step 5: Solve for x
    x = 4,476.40/78.56
  6. Step 6: Final answer
    x = 56.98

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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.