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Finding the Fourth Proportional to 78.16, 107.85 and 45.40

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Solution

The fourth proportional to 78.16, 107.85 and 45.40 is: 62.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.16 : 107.85 = 45.40 : x
  2. Step 2: Convert to fraction form
    78.16/107.85 = 45.40/x
  3. Step 3: Cross multiply
    78.16x = 107.85 × 45.40
  4. Step 4: Simplify right side
    78.16x = 4,895.68
  5. Step 5: Solve for x
    x = 4,895.68/78.16
  6. Step 6: Final answer
    x = 62.63

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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.