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Finding the Fourth Proportional to 56.64, 78.12 and 49.20

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Solution

The fourth proportional to 56.64, 78.12 and 49.20 is: 67.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.64 : 78.12 = 49.20 : x
  2. Step 2: Convert to fraction form
    56.64/78.12 = 49.20/x
  3. Step 3: Cross multiply
    56.64x = 78.12 × 49.20
  4. Step 4: Simplify right side
    56.64x = 3,843.50
  5. Step 5: Solve for x
    x = 3,843.50/56.64
  6. Step 6: Final answer
    x = 67.86

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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.