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Finding the Fourth Proportional to 208.16, 312.30 and 78.22

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Solution

The fourth proportional to 208.16, 312.30 and 78.22 is: 117.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.16 : 312.30 = 78.22 : x
  2. Step 2: Convert to fraction form
    208.16/312.30 = 78.22/x
  3. Step 3: Cross multiply
    208.16x = 312.30 × 78.22
  4. Step 4: Simplify right side
    208.16x = 24,428.11
  5. Step 5: Solve for x
    x = 24,428.11/208.16
  6. Step 6: Final answer
    x = 117.35

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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.