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Finding the Fourth Proportional to 647.65, 971.64 and 208.90

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Solution

The fourth proportional to 647.65, 971.64 and 208.90 is: 313.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.65 : 971.64 = 208.90 : x
  2. Step 2: Convert to fraction form
    647.65/971.64 = 208.90/x
  3. Step 3: Cross multiply
    647.65x = 971.64 × 208.90
  4. Step 4: Simplify right side
    647.65x = 202,975.60
  5. Step 5: Solve for x
    x = 202,975.60/647.65
  6. Step 6: Final answer
    x = 313.40

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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.