Home / 789-1,089.09-478.50

Finding the Fourth Proportional to 789, 1,089.09 and 478.50

Calculator

Solution

The fourth proportional to 789, 1,089.09 and 478.50 is: 660.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    789 : 1,089.09 = 478.50 : x
  2. Step 2: Convert to fraction form
    789/1,089.09 = 478.50/x
  3. Step 3: Cross multiply
    789x = 1,089.09 × 478.50
  4. Step 4: Simplify right side
    789x = 521,129.57
  5. Step 5: Solve for x
    x = 521,129.57/789
  6. Step 6: Final answer
    x = 660.49

Related Problems

Find fourth proportional to 394.50, 544.55 and 239.25
Half scale
Find fourth proportional to 1,578, 2,178.18 and 957
Double scale
Find fourth proportional to 790, 1,090.47 and 479.50
Similar ratio
Find fourth proportional to 1,183.50, 1,633.64 and 717.75
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.