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Finding the Fourth Proportional to 752.64, 1,038.76 and 421.20

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Solution

The fourth proportional to 752.64, 1,038.76 and 421.20 is: 581.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    752.64 : 1,038.76 = 421.20 : x
  2. Step 2: Convert to fraction form
    752.64/1,038.76 = 421.20/x
  3. Step 3: Cross multiply
    752.64x = 1,038.76 × 421.20
  4. Step 4: Simplify right side
    752.64x = 437,525.71
  5. Step 5: Solve for x
    x = 437,525.71/752.64
  6. Step 6: Final answer
    x = 581.32

Related Problems

Find fourth proportional to 376.32, 519.38 and 210.60
Half scale
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Double scale
Find fourth proportional to 753.64, 1,040.14 and 422.20
Similar ratio
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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.