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Finding the Fourth Proportional to 687.90, 949.38 and 389.19

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Solution

The fourth proportional to 687.90, 949.38 and 389.19 is: 537.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.90 : 949.38 = 389.19 : x
  2. Step 2: Convert to fraction form
    687.90/949.38 = 389.19/x
  3. Step 3: Cross multiply
    687.90x = 949.38 × 389.19
  4. Step 4: Simplify right side
    687.90x = 369,489.20
  5. Step 5: Solve for x
    x = 369,489.20/687.90
  6. Step 6: Final answer
    x = 537.13

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1.5x scale

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.