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Finding the Fourth Proportional to 689.76, 956.16 and 645.60

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Solution

The fourth proportional to 689.76, 956.16 and 645.60 is: 894.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.76 : 956.16 = 645.60 : x
  2. Step 2: Convert to fraction form
    689.76/956.16 = 645.60/x
  3. Step 3: Cross multiply
    689.76x = 956.16 × 645.60
  4. Step 4: Simplify right side
    689.76x = 617,296.90
  5. Step 5: Solve for x
    x = 617,296.90/689.76
  6. Step 6: Final answer
    x = 894.94

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.