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Finding the Fourth Proportional to 78.10, 117.02 and 39.58

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Solution

The fourth proportional to 78.10, 117.02 and 39.58 is: 59.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.10 : 117.02 = 39.58 : x
  2. Step 2: Convert to fraction form
    78.10/117.02 = 39.58/x
  3. Step 3: Cross multiply
    78.10x = 117.02 × 39.58
  4. Step 4: Simplify right side
    78.10x = 4,631.65
  5. Step 5: Solve for x
    x = 4,631.65/78.10
  6. Step 6: Final answer
    x = 59.30

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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.