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Finding the Fourth Proportional to 209.99, 315 and 65.72

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Solution

The fourth proportional to 209.99, 315 and 65.72 is: 98.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.99 : 315 = 65.72 : x
  2. Step 2: Convert to fraction form
    209.99/315 = 65.72/x
  3. Step 3: Cross multiply
    209.99x = 315 × 65.72
  4. Step 4: Simplify right side
    209.99x = 20,701.80
  5. Step 5: Solve for x
    x = 20,701.80/209.99
  6. Step 6: Final answer
    x = 98.58

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.