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Finding the Fourth Proportional to 72.29, 99.79 and 56.72

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Solution

The fourth proportional to 72.29, 99.79 and 56.72 is: 78.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.29 : 99.79 = 56.72 : x
  2. Step 2: Convert to fraction form
    72.29/99.79 = 56.72/x
  3. Step 3: Cross multiply
    72.29x = 99.79 × 56.72
  4. Step 4: Simplify right side
    72.29x = 5,660.20
  5. Step 5: Solve for x
    x = 5,660.20/72.29
  6. Step 6: Final answer
    x = 78.30

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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.