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Finding the Fourth Proportional to 1,378.86, 2,068.29 and 405.64

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Solution

The fourth proportional to 1,378.86, 2,068.29 and 405.64 is: 608.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.86 : 2,068.29 = 405.64 : x
  2. Step 2: Convert to fraction form
    1,378.86/2,068.29 = 405.64/x
  3. Step 3: Cross multiply
    1,378.86x = 2,068.29 × 405.64
  4. Step 4: Simplify right side
    1,378.86x = 838,986.86
  5. Step 5: Solve for x
    x = 838,986.86/1,378.86
  6. Step 6: Final answer
    x = 608.46

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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.