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Finding the Fourth Proportional to 212.55, 318.84 and 66.30

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Solution

The fourth proportional to 212.55, 318.84 and 66.30 is: 99.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.55 : 318.84 = 66.30 : x
  2. Step 2: Convert to fraction form
    212.55/318.84 = 66.30/x
  3. Step 3: Cross multiply
    212.55x = 318.84 × 66.30
  4. Step 4: Simplify right side
    212.55x = 21,139.81
  5. Step 5: Solve for x
    x = 21,139.81/212.55
  6. Step 6: Final answer
    x = 99.46

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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.