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Finding the Fourth Proportional to 66.65, 99.97 and 21.00

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Solution

The fourth proportional to 66.65, 99.97 and 21.00 is: 31.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.65 : 99.97 = 21.00 : x
  2. Step 2: Convert to fraction form
    66.65/99.97 = 21.00/x
  3. Step 3: Cross multiply
    66.65x = 99.97 × 21.00
  4. Step 4: Simplify right side
    66.65x = 2,099.13
  5. Step 5: Solve for x
    x = 2,099.13/66.65
  6. Step 6: Final answer
    x = 31.50

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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.