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Finding the Fourth Proportional to 620.64, 856.40 and 421.92

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Solution

The fourth proportional to 620.64, 856.40 and 421.92 is: 582.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.64 : 856.40 = 421.92 : x
  2. Step 2: Convert to fraction form
    620.64/856.40 = 421.92/x
  3. Step 3: Cross multiply
    620.64x = 856.40 × 421.92
  4. Step 4: Simplify right side
    620.64x = 361,332.29
  5. Step 5: Solve for x
    x = 361,332.29/620.64
  6. Step 6: Final answer
    x = 582.19

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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.