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Finding the Fourth Proportional to 78.02, 117.02 and 21.02

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Solution

The fourth proportional to 78.02, 117.02 and 21.02 is: 31.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.02 : 117.02 = 21.02 : x
  2. Step 2: Convert to fraction form
    78.02/117.02 = 21.02/x
  3. Step 3: Cross multiply
    78.02x = 117.02 × 21.02
  4. Step 4: Simplify right side
    78.02x = 2,459.76
  5. Step 5: Solve for x
    x = 2,459.76/78.02
  6. Step 6: Final answer
    x = 31.53

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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.