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Finding the Fourth Proportional to 641.68, 885.68 and 405.48

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Solution

The fourth proportional to 641.68, 885.68 and 405.48 is: 559.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.68 : 885.68 = 405.48 : x
  2. Step 2: Convert to fraction form
    641.68/885.68 = 405.48/x
  3. Step 3: Cross multiply
    641.68x = 885.68 × 405.48
  4. Step 4: Simplify right side
    641.68x = 359,128.13
  5. Step 5: Solve for x
    x = 359,128.13/641.68
  6. Step 6: Final answer
    x = 559.67

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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.