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Finding the Fourth Proportional to 78.15, 107.85 and 47.06

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Solution

The fourth proportional to 78.15, 107.85 and 47.06 is: 64.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.15 : 107.85 = 47.06 : x
  2. Step 2: Convert to fraction form
    78.15/107.85 = 47.06/x
  3. Step 3: Cross multiply
    78.15x = 107.85 × 47.06
  4. Step 4: Simplify right side
    78.15x = 5,075.42
  5. Step 5: Solve for x
    x = 5,075.42/78.15
  6. Step 6: Final answer
    x = 64.94

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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.