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Finding the Fourth Proportional to 72.45, 99.88 and 56.85

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Solution

The fourth proportional to 72.45, 99.88 and 56.85 is: 78.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.45 : 99.88 = 56.85 : x
  2. Step 2: Convert to fraction form
    72.45/99.88 = 56.85/x
  3. Step 3: Cross multiply
    72.45x = 99.88 × 56.85
  4. Step 4: Simplify right side
    72.45x = 5,678.18
  5. Step 5: Solve for x
    x = 5,678.18/72.45
  6. Step 6: Final answer
    x = 78.37

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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.