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Finding the Fourth Proportional to 715.50, 986.67 and 645.66

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Solution

The fourth proportional to 715.50, 986.67 and 645.66 is: 890.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.50 : 986.67 = 645.66 : x
  2. Step 2: Convert to fraction form
    715.50/986.67 = 645.66/x
  3. Step 3: Cross multiply
    715.50x = 986.67 × 645.66
  4. Step 4: Simplify right side
    715.50x = 637,053.35
  5. Step 5: Solve for x
    x = 637,053.35/715.50
  6. Step 6: Final answer
    x = 890.36

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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.