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Finding the Fourth Proportional to 723.12, 1,085.29 and 312.57

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Solution

The fourth proportional to 723.12, 1,085.29 and 312.57 is: 469.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    723.12 : 1,085.29 = 312.57 : x
  2. Step 2: Convert to fraction form
    723.12/1,085.29 = 312.57/x
  3. Step 3: Cross multiply
    723.12x = 1,085.29 × 312.57
  4. Step 4: Simplify right side
    723.12x = 339,228.31
  5. Step 5: Solve for x
    x = 339,228.31/723.12
  6. Step 6: Final answer
    x = 469.12

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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.