Home / 726.40-1,089.60-644.80

Finding the Fourth Proportional to 726.40, 1,089.60 and 644.80

Calculator

Solution

The fourth proportional to 726.40, 1,089.60 and 644.80 is: 967.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    726.40 : 1,089.60 = 644.80 : x
  2. Step 2: Convert to fraction form
    726.40/1,089.60 = 644.80/x
  3. Step 3: Cross multiply
    726.40x = 1,089.60 × 644.80
  4. Step 4: Simplify right side
    726.40x = 702,574.08
  5. Step 5: Solve for x
    x = 702,574.08/726.40
  6. Step 6: Final answer
    x = 967.20

Related Problems

Find fourth proportional to 363.20, 544.80 and 322.40
Half scale
Find fourth proportional to 1,452.80, 2,179.20 and 1,289.60
Double scale
Find fourth proportional to 727.40, 1,091.10 and 645.80
Similar ratio
Find fourth proportional to 1,089.60, 1,634.40 and 967.20
1.5x scale

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.