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Finding the Fourth Proportional to 713.80, 1,069.90 and 405.80

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Solution

The fourth proportional to 713.80, 1,069.90 and 405.80 is: 608.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    713.80 : 1,069.90 = 405.80 : x
  2. Step 2: Convert to fraction form
    713.80/1,069.90 = 405.80/x
  3. Step 3: Cross multiply
    713.80x = 1,069.90 × 405.80
  4. Step 4: Simplify right side
    713.80x = 434,165.42
  5. Step 5: Solve for x
    x = 434,165.42/713.80
  6. Step 6: Final answer
    x = 608.25

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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.