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Finding the Fourth Proportional to 210.65, 316.13 and 82.40

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Solution

The fourth proportional to 210.65, 316.13 and 82.40 is: 123.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.65 : 316.13 = 82.40 : x
  2. Step 2: Convert to fraction form
    210.65/316.13 = 82.40/x
  3. Step 3: Cross multiply
    210.65x = 316.13 × 82.40
  4. Step 4: Simplify right side
    210.65x = 26,047.12
  5. Step 5: Solve for x
    x = 26,047.12/210.65
  6. Step 6: Final answer
    x = 123.65

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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.