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Finding the Fourth Proportional to 210.40, 312.55 and 206.80

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Solution

The fourth proportional to 210.40, 312.55 and 206.80 is: 307.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.40 : 312.55 = 206.80 : x
  2. Step 2: Convert to fraction form
    210.40/312.55 = 206.80/x
  3. Step 3: Cross multiply
    210.40x = 312.55 × 206.80
  4. Step 4: Simplify right side
    210.40x = 64,635.34
  5. Step 5: Solve for x
    x = 64,635.34/210.40
  6. Step 6: Final answer
    x = 307.20

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.