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Finding the Fourth Proportional to 647.84, 971.76 and 520.40

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Solution

The fourth proportional to 647.84, 971.76 and 520.40 is: 780.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.84 : 971.76 = 520.40 : x
  2. Step 2: Convert to fraction form
    647.84/971.76 = 520.40/x
  3. Step 3: Cross multiply
    647.84x = 971.76 × 520.40
  4. Step 4: Simplify right side
    647.84x = 505,703.90
  5. Step 5: Solve for x
    x = 505,703.90/647.84
  6. Step 6: Final answer
    x = 780.60

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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.