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Finding the Fourth Proportional to 818.45, 1,129.40 and 486.90

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Solution

The fourth proportional to 818.45, 1,129.40 and 486.90 is: 671.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.45 : 1,129.40 = 486.90 : x
  2. Step 2: Convert to fraction form
    818.45/1,129.40 = 486.90/x
  3. Step 3: Cross multiply
    818.45x = 1,129.40 × 486.90
  4. Step 4: Simplify right side
    818.45x = 549,904.86
  5. Step 5: Solve for x
    x = 549,904.86/818.45
  6. Step 6: Final answer
    x = 671.89

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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.