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Finding the Fourth Proportional to 1,318.99, 1,978.65 and 486.11

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Solution

The fourth proportional to 1,318.99, 1,978.65 and 486.11 is: 729.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,318.99 : 1,978.65 = 486.11 : x
  2. Step 2: Convert to fraction form
    1,318.99/1,978.65 = 486.11/x
  3. Step 3: Cross multiply
    1,318.99x = 1,978.65 × 486.11
  4. Step 4: Simplify right side
    1,318.99x = 961,831.66
  5. Step 5: Solve for x
    x = 961,831.66/1,318.99
  6. Step 6: Final answer
    x = 729.22

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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.