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Finding the Fourth Proportional to 64.45, 89 and 42.72

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Solution

The fourth proportional to 64.45, 89 and 42.72 is: 58.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.45 : 89 = 42.72 : x
  2. Step 2: Convert to fraction form
    64.45/89 = 42.72/x
  3. Step 3: Cross multiply
    64.45x = 89 × 42.72
  4. Step 4: Simplify right side
    64.45x = 3,802.08
  5. Step 5: Solve for x
    x = 3,802.08/64.45
  6. Step 6: Final answer
    x = 58.99

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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.