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Finding the Fourth Proportional to 715.79, 986.84 and 642.89

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Solution

The fourth proportional to 715.79, 986.84 and 642.89 is: 886.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.79 : 986.84 = 642.89 : x
  2. Step 2: Convert to fraction form
    715.79/986.84 = 642.89/x
  3. Step 3: Cross multiply
    715.79x = 986.84 × 642.89
  4. Step 4: Simplify right side
    715.79x = 634,429.57
  5. Step 5: Solve for x
    x = 634,429.57/715.79
  6. Step 6: Final answer
    x = 886.33

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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.