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Finding the Fourth Proportional to 890.40, 1,228.80 and 497.42

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Solution

The fourth proportional to 890.40, 1,228.80 and 497.42 is: 686.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.40 : 1,228.80 = 497.42 : x
  2. Step 2: Convert to fraction form
    890.40/1,228.80 = 497.42/x
  3. Step 3: Cross multiply
    890.40x = 1,228.80 × 497.42
  4. Step 4: Simplify right side
    890.40x = 611,234.63
  5. Step 5: Solve for x
    x = 611,234.63/890.40
  6. Step 6: Final answer
    x = 686.47

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.