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Finding the Fourth Proportional to 66.65, 99.81 and 39.51

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Solution

The fourth proportional to 66.65, 99.81 and 39.51 is: 59.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.65 : 99.81 = 39.51 : x
  2. Step 2: Convert to fraction form
    66.65/99.81 = 39.51/x
  3. Step 3: Cross multiply
    66.65x = 99.81 × 39.51
  4. Step 4: Simplify right side
    66.65x = 3,943.30
  5. Step 5: Solve for x
    x = 3,943.30/66.65
  6. Step 6: Final answer
    x = 59.17

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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.