Home / 868.60-1,199.10-728.20

Finding the Fourth Proportional to 868.60, 1,199.10 and 728.20

Calculator

Solution

The fourth proportional to 868.60, 1,199.10 and 728.20 is: 1,005.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    868.60 : 1,199.10 = 728.20 : x
  2. Step 2: Convert to fraction form
    868.60/1,199.10 = 728.20/x
  3. Step 3: Cross multiply
    868.60x = 1,199.10 × 728.20
  4. Step 4: Simplify right side
    868.60x = 873,184.62
  5. Step 5: Solve for x
    x = 873,184.62/868.60
  6. Step 6: Final answer
    x = 1,005.28

Related Problems

Find fourth proportional to 434.30, 599.55 and 364.10
Half scale
Find fourth proportional to 1,737.20, 2,398.20 and 1,456.40
Double scale
Find fourth proportional to 869.60, 1,200.48 and 729.20
Similar ratio
Find fourth proportional to 1,302.90, 1,798.65 and 1,092.30
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.