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Finding the Fourth Proportional to 56.90, 78.57 and 39.49

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Solution

The fourth proportional to 56.90, 78.57 and 39.49 is: 54.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.90 : 78.57 = 39.49 : x
  2. Step 2: Convert to fraction form
    56.90/78.57 = 39.49/x
  3. Step 3: Cross multiply
    56.90x = 78.57 × 39.49
  4. Step 4: Simplify right side
    56.90x = 3,102.53
  5. Step 5: Solve for x
    x = 3,102.53/56.90
  6. Step 6: Final answer
    x = 54.52

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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.