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Finding the Fourth Proportional to 528.70, 791.70 and 420.70

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Solution

The fourth proportional to 528.70, 791.70 and 420.70 is: 629.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    528.70 : 791.70 = 420.70 : x
  2. Step 2: Convert to fraction form
    528.70/791.70 = 420.70/x
  3. Step 3: Cross multiply
    528.70x = 791.70 × 420.70
  4. Step 4: Simplify right side
    528.70x = 333,068.19
  5. Step 5: Solve for x
    x = 333,068.19/528.70
  6. Step 6: Final answer
    x = 629.98

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.