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Finding the Fourth Proportional to 76.60, 105.64 and 64.93

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Solution

The fourth proportional to 76.60, 105.64 and 64.93 is: 89.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.60 : 105.64 = 64.93 : x
  2. Step 2: Convert to fraction form
    76.60/105.64 = 64.93/x
  3. Step 3: Cross multiply
    76.60x = 105.64 × 64.93
  4. Step 4: Simplify right side
    76.60x = 6,859.63
  5. Step 5: Solve for x
    x = 6,859.63/76.60
  6. Step 6: Final answer
    x = 89.55

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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.