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Finding the Fourth Proportional to 64.60, 89.18 and 42.80

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Solution

The fourth proportional to 64.60, 89.18 and 42.80 is: 59.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.60 : 89.18 = 42.80 : x
  2. Step 2: Convert to fraction form
    64.60/89.18 = 42.80/x
  3. Step 3: Cross multiply
    64.60x = 89.18 × 42.80
  4. Step 4: Simplify right side
    64.60x = 3,816.47
  5. Step 5: Solve for x
    x = 3,816.47/64.60
  6. Step 6: Final answer
    x = 59.08

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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.