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Finding the Fourth Proportional to 407.86, 611.79 and 99.72

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Solution

The fourth proportional to 407.86, 611.79 and 99.72 is: 149.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    407.86 : 611.79 = 99.72 : x
  2. Step 2: Convert to fraction form
    407.86/611.79 = 99.72/x
  3. Step 3: Cross multiply
    407.86x = 611.79 × 99.72
  4. Step 4: Simplify right side
    407.86x = 61,005.40
  5. Step 5: Solve for x
    x = 61,005.40/407.86
  6. Step 6: Final answer
    x = 149.57

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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.