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Finding the Fourth Proportional to 645.59, 891.21 and 412.85

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Solution

The fourth proportional to 645.59, 891.21 and 412.85 is: 569.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.59 : 891.21 = 412.85 : x
  2. Step 2: Convert to fraction form
    645.59/891.21 = 412.85/x
  3. Step 3: Cross multiply
    645.59x = 891.21 × 412.85
  4. Step 4: Simplify right side
    645.59x = 367,931.59
  5. Step 5: Solve for x
    x = 367,931.59/645.59
  6. Step 6: Final answer
    x = 569.92

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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.