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Finding the Fourth Proportional to 874.89, 1,312.20 and 319.50

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Solution

The fourth proportional to 874.89, 1,312.20 and 319.50 is: 479.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    874.89 : 1,312.20 = 319.50 : x
  2. Step 2: Convert to fraction form
    874.89/1,312.20 = 319.50/x
  3. Step 3: Cross multiply
    874.89x = 1,312.20 × 319.50
  4. Step 4: Simplify right side
    874.89x = 419,247.90
  5. Step 5: Solve for x
    x = 419,247.90/874.89
  6. Step 6: Final answer
    x = 479.20

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1.5x scale

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.