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Finding the Fourth Proportional to 420.15, 629.76 and 317.10

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Solution

The fourth proportional to 420.15, 629.76 and 317.10 is: 475.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.15 : 629.76 = 317.10 : x
  2. Step 2: Convert to fraction form
    420.15/629.76 = 317.10/x
  3. Step 3: Cross multiply
    420.15x = 629.76 × 317.10
  4. Step 4: Simplify right side
    420.15x = 199,699.06
  5. Step 5: Solve for x
    x = 199,699.06/420.15
  6. Step 6: Final answer
    x = 475.30

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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.