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Finding the Fourth Proportional to 717.50, 990.15 and 407

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Solution

The fourth proportional to 717.50, 990.15 and 407 is: 561.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.50 : 990.15 = 407 : x
  2. Step 2: Convert to fraction form
    717.50/990.15 = 407/x
  3. Step 3: Cross multiply
    717.50x = 990.15 × 407
  4. Step 4: Simplify right side
    717.50x = 402,991.05
  5. Step 5: Solve for x
    x = 402,991.05/717.50
  6. Step 6: Final answer
    x = 561.66

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.