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Finding the Fourth Proportional to 1,368.40, 1,887.96 and 778.90

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Solution

The fourth proportional to 1,368.40, 1,887.96 and 778.90 is: 1,074.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,368.40 : 1,887.96 = 778.90 : x
  2. Step 2: Convert to fraction form
    1,368.40/1,887.96 = 778.90/x
  3. Step 3: Cross multiply
    1,368.40x = 1,887.96 × 778.90
  4. Step 4: Simplify right side
    1,368.40x = 1,470,532.04
  5. Step 5: Solve for x
    x = 1,470,532.04/1,368.40
  6. Step 6: Final answer
    x = 1,074.64

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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.