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Finding the Fourth Proportional to 420.63, 627.50 and 391.17

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Solution

The fourth proportional to 420.63, 627.50 and 391.17 is: 583.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.63 : 627.50 = 391.17 : x
  2. Step 2: Convert to fraction form
    420.63/627.50 = 391.17/x
  3. Step 3: Cross multiply
    420.63x = 627.50 × 391.17
  4. Step 4: Simplify right side
    420.63x = 245,457.22
  5. Step 5: Solve for x
    x = 245,457.22/420.63
  6. Step 6: Final answer
    x = 583.55

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.