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Finding the Fourth Proportional to 678.40, 1,017.60 and 313.08

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Solution

The fourth proportional to 678.40, 1,017.60 and 313.08 is: 469.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.40 : 1,017.60 = 313.08 : x
  2. Step 2: Convert to fraction form
    678.40/1,017.60 = 313.08/x
  3. Step 3: Cross multiply
    678.40x = 1,017.60 × 313.08
  4. Step 4: Simplify right side
    678.40x = 318,590.21
  5. Step 5: Solve for x
    x = 318,590.21/678.40
  6. Step 6: Final answer
    x = 469.62

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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.