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Finding the Fourth Proportional to 970.80, 1,339.38 and 621.70

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Solution

The fourth proportional to 970.80, 1,339.38 and 621.70 is: 857.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.80 : 1,339.38 = 621.70 : x
  2. Step 2: Convert to fraction form
    970.80/1,339.38 = 621.70/x
  3. Step 3: Cross multiply
    970.80x = 1,339.38 × 621.70
  4. Step 4: Simplify right side
    970.80x = 832,692.55
  5. Step 5: Solve for x
    x = 832,692.55/970.80
  6. Step 6: Final answer
    x = 857.74

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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.