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Finding the Fourth Proportional to 620.90, 938.70 and 615.78

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Solution

The fourth proportional to 620.90, 938.70 and 615.78 is: 930.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.90 : 938.70 = 615.78 : x
  2. Step 2: Convert to fraction form
    620.90/938.70 = 615.78/x
  3. Step 3: Cross multiply
    620.90x = 938.70 × 615.78
  4. Step 4: Simplify right side
    620.90x = 578,030.91
  5. Step 5: Solve for x
    x = 578,030.91/620.90
  6. Step 6: Final answer
    x = 930.95

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.