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Finding the Fourth Proportional to 639.74, 882.96 and 407

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Solution

The fourth proportional to 639.74, 882.96 and 407 is: 561.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.74 : 882.96 = 407 : x
  2. Step 2: Convert to fraction form
    639.74/882.96 = 407/x
  3. Step 3: Cross multiply
    639.74x = 882.96 × 407
  4. Step 4: Simplify right side
    639.74x = 359,364.72
  5. Step 5: Solve for x
    x = 359,364.72/639.74
  6. Step 6: Final answer
    x = 561.74

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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.