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Finding the Fourth Proportional to 815.85, 1,223.90 and 405.02

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Solution

The fourth proportional to 815.85, 1,223.90 and 405.02 is: 607.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.85 : 1,223.90 = 405.02 : x
  2. Step 2: Convert to fraction form
    815.85/1,223.90 = 405.02/x
  3. Step 3: Cross multiply
    815.85x = 1,223.90 × 405.02
  4. Step 4: Simplify right side
    815.85x = 495,695.83
  5. Step 5: Solve for x
    x = 495,695.83/815.85
  6. Step 6: Final answer
    x = 607.58

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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.