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Finding the Fourth Proportional to 61.80, 85.20 and 52.08

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Solution

The fourth proportional to 61.80, 85.20 and 52.08 is: 71.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.80 : 85.20 = 52.08 : x
  2. Step 2: Convert to fraction form
    61.80/85.20 = 52.08/x
  3. Step 3: Cross multiply
    61.80x = 85.20 × 52.08
  4. Step 4: Simplify right side
    61.80x = 4,437.22
  5. Step 5: Solve for x
    x = 4,437.22/61.80
  6. Step 6: Final answer
    x = 71.80

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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.