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Finding the Fourth Proportional to 667.98, 921.47 and 621.05

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Solution

The fourth proportional to 667.98, 921.47 and 621.05 is: 856.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.98 : 921.47 = 621.05 : x
  2. Step 2: Convert to fraction form
    667.98/921.47 = 621.05/x
  3. Step 3: Cross multiply
    667.98x = 921.47 × 621.05
  4. Step 4: Simplify right side
    667.98x = 572,271.23
  5. Step 5: Solve for x
    x = 572,271.23/667.98
  6. Step 6: Final answer
    x = 856.72

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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.