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Finding the Fourth Proportional to 78.15, 107.61 and 56.28

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Solution

The fourth proportional to 78.15, 107.61 and 56.28 is: 77.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.15 : 107.61 = 56.28 : x
  2. Step 2: Convert to fraction form
    78.15/107.61 = 56.28/x
  3. Step 3: Cross multiply
    78.15x = 107.61 × 56.28
  4. Step 4: Simplify right side
    78.15x = 6,056.29
  5. Step 5: Solve for x
    x = 6,056.29/78.15
  6. Step 6: Final answer
    x = 77.50

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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.