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Finding the Fourth Proportional to 642.93, 887.28 and 485.28

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Solution

The fourth proportional to 642.93, 887.28 and 485.28 is: 669.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.93 : 887.28 = 485.28 : x
  2. Step 2: Convert to fraction form
    642.93/887.28 = 485.28/x
  3. Step 3: Cross multiply
    642.93x = 887.28 × 485.28
  4. Step 4: Simplify right side
    642.93x = 430,577.42
  5. Step 5: Solve for x
    x = 430,577.42/642.93
  6. Step 6: Final answer
    x = 669.72

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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.