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Finding the Fourth Proportional to 659.90, 989.40 and 313.40

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Solution

The fourth proportional to 659.90, 989.40 and 313.40 is: 469.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.90 : 989.40 = 313.40 : x
  2. Step 2: Convert to fraction form
    659.90/989.40 = 313.40/x
  3. Step 3: Cross multiply
    659.90x = 989.40 × 313.40
  4. Step 4: Simplify right side
    659.90x = 310,077.96
  5. Step 5: Solve for x
    x = 310,077.96/659.90
  6. Step 6: Final answer
    x = 469.89

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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.