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Finding the Fourth Proportional to 407.09, 561.26 and 312.66

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Solution

The fourth proportional to 407.09, 561.26 and 312.66 is: 431.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    407.09 : 561.26 = 312.66 : x
  2. Step 2: Convert to fraction form
    407.09/561.26 = 312.66/x
  3. Step 3: Cross multiply
    407.09x = 561.26 × 312.66
  4. Step 4: Simplify right side
    407.09x = 175,483.55
  5. Step 5: Solve for x
    x = 175,483.55/407.09
  6. Step 6: Final answer
    x = 431.07

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.