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Finding the Fourth Proportional to 715.76, 985.38 and 628.40

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Solution

The fourth proportional to 715.76, 985.38 and 628.40 is: 865.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.76 : 985.38 = 628.40 : x
  2. Step 2: Convert to fraction form
    715.76/985.38 = 628.40/x
  3. Step 3: Cross multiply
    715.76x = 985.38 × 628.40
  4. Step 4: Simplify right side
    715.76x = 619,212.79
  5. Step 5: Solve for x
    x = 619,212.79/715.76
  6. Step 6: Final answer
    x = 865.11

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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.