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Finding the Fourth Proportional to 485.55, 670.74 and 387.18

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Solution

The fourth proportional to 485.55, 670.74 and 387.18 is: 534.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.55 : 670.74 = 387.18 : x
  2. Step 2: Convert to fraction form
    485.55/670.74 = 387.18/x
  3. Step 3: Cross multiply
    485.55x = 670.74 × 387.18
  4. Step 4: Simplify right side
    485.55x = 259,697.11
  5. Step 5: Solve for x
    x = 259,697.11/485.55
  6. Step 6: Final answer
    x = 534.85

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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.