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Finding the Fourth Proportional to 687.18, 949.68 and 621.30

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Solution

The fourth proportional to 687.18, 949.68 and 621.30 is: 858.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.18 : 949.68 = 621.30 : x
  2. Step 2: Convert to fraction form
    687.18/949.68 = 621.30/x
  3. Step 3: Cross multiply
    687.18x = 949.68 × 621.30
  4. Step 4: Simplify right side
    687.18x = 590,036.18
  5. Step 5: Solve for x
    x = 590,036.18/687.18
  6. Step 6: Final answer
    x = 858.63

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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.