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Finding the Fourth Proportional to 72.85, 109.28 and 21.50

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Solution

The fourth proportional to 72.85, 109.28 and 21.50 is: 32.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.85 : 109.28 = 21.50 : x
  2. Step 2: Convert to fraction form
    72.85/109.28 = 21.50/x
  3. Step 3: Cross multiply
    72.85x = 109.28 × 21.50
  4. Step 4: Simplify right side
    72.85x = 2,349.52
  5. Step 5: Solve for x
    x = 2,349.52/72.85
  6. Step 6: Final answer
    x = 32.25

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.