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Finding the Fourth Proportional to 77.12, 106.31 and 56.40

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Solution

The fourth proportional to 77.12, 106.31 and 56.40 is: 77.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.12 : 106.31 = 56.40 : x
  2. Step 2: Convert to fraction form
    77.12/106.31 = 56.40/x
  3. Step 3: Cross multiply
    77.12x = 106.31 × 56.40
  4. Step 4: Simplify right side
    77.12x = 5,995.63
  5. Step 5: Solve for x
    x = 5,995.63/77.12
  6. Step 6: Final answer
    x = 77.75

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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.