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Finding the Fourth Proportional to 309.99, 427.80 and 185.61

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Solution

The fourth proportional to 309.99, 427.80 and 185.61 is: 256.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.99 : 427.80 = 185.61 : x
  2. Step 2: Convert to fraction form
    309.99/427.80 = 185.61/x
  3. Step 3: Cross multiply
    309.99x = 427.80 × 185.61
  4. Step 4: Simplify right side
    309.99x = 79,403.96
  5. Step 5: Solve for x
    x = 79,403.96/309.99
  6. Step 6: Final answer
    x = 256.15

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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.