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Finding the Fourth Proportional to 56.40, 77.72 and 39.98

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Solution

The fourth proportional to 56.40, 77.72 and 39.98 is: 55.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.40 : 77.72 = 39.98 : x
  2. Step 2: Convert to fraction form
    56.40/77.72 = 39.98/x
  3. Step 3: Cross multiply
    56.40x = 77.72 × 39.98
  4. Step 4: Simplify right side
    56.40x = 3,107.25
  5. Step 5: Solve for x
    x = 3,107.25/56.40
  6. Step 6: Final answer
    x = 55.09

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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.