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Finding the Fourth Proportional to 51.90, 78.45 and 51.90

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Solution

The fourth proportional to 51.90, 78.45 and 51.90 is: 78.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.90 : 78.45 = 51.90 : x
  2. Step 2: Convert to fraction form
    51.90/78.45 = 51.90/x
  3. Step 3: Cross multiply
    51.90x = 78.45 × 51.90
  4. Step 4: Simplify right side
    51.90x = 4,071.56
  5. Step 5: Solve for x
    x = 4,071.56/51.90
  6. Step 6: Final answer
    x = 78.45

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.