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Finding the Fourth Proportional to 56.90, 78.36 and 55.64

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Solution

The fourth proportional to 56.90, 78.36 and 55.64 is: 76.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.90 : 78.36 = 55.64 : x
  2. Step 2: Convert to fraction form
    56.90/78.36 = 55.64/x
  3. Step 3: Cross multiply
    56.90x = 78.36 × 55.64
  4. Step 4: Simplify right side
    56.90x = 4,359.95
  5. Step 5: Solve for x
    x = 4,359.95/56.90
  6. Step 6: Final answer
    x = 76.62

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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.