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Finding the Fourth Proportional to 785.46, 1,178.95 and 420.50

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Solution

The fourth proportional to 785.46, 1,178.95 and 420.50 is: 631.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    785.46 : 1,178.95 = 420.50 : x
  2. Step 2: Convert to fraction form
    785.46/1,178.95 = 420.50/x
  3. Step 3: Cross multiply
    785.46x = 1,178.95 × 420.50
  4. Step 4: Simplify right side
    785.46x = 495,748.48
  5. Step 5: Solve for x
    x = 495,748.48/785.46
  6. Step 6: Final answer
    x = 631.16

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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.