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Finding the Fourth Proportional to 561.21, 840.68 and 415.40

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Solution

The fourth proportional to 561.21, 840.68 and 415.40 is: 622.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    561.21 : 840.68 = 415.40 : x
  2. Step 2: Convert to fraction form
    561.21/840.68 = 415.40/x
  3. Step 3: Cross multiply
    561.21x = 840.68 × 415.40
  4. Step 4: Simplify right side
    561.21x = 349,212.19
  5. Step 5: Solve for x
    x = 349,212.19/561.21
  6. Step 6: Final answer
    x = 622.25

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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.