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Finding the Fourth Proportional to 646.20, 890.82 and 621

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Solution

The fourth proportional to 646.20, 890.82 and 621 is: 856.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    646.20 : 890.82 = 621 : x
  2. Step 2: Convert to fraction form
    646.20/890.82 = 621/x
  3. Step 3: Cross multiply
    646.20x = 890.82 × 621
  4. Step 4: Simplify right side
    646.20x = 553,199.22
  5. Step 5: Solve for x
    x = 553,199.22/646.20
  6. Step 6: Final answer
    x = 856.08

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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.