Home / 505.20-756.20-489.20

Finding the Fourth Proportional to 505.20, 756.20 and 489.20

Calculator

Solution

The fourth proportional to 505.20, 756.20 and 489.20 is: 732.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    505.20 : 756.20 = 489.20 : x
  2. Step 2: Convert to fraction form
    505.20/756.20 = 489.20/x
  3. Step 3: Cross multiply
    505.20x = 756.20 × 489.20
  4. Step 4: Simplify right side
    505.20x = 369,933.04
  5. Step 5: Solve for x
    x = 369,933.04/505.20
  6. Step 6: Final answer
    x = 732.25

Related Problems

Find fourth proportional to 252.60, 378.10 and 244.60
Half scale
Find fourth proportional to 1,010.40, 1,512.40 and 978.40
Double scale
Find fourth proportional to 506.20, 757.70 and 490.20
Similar ratio
Find fourth proportional to 757.80, 1,134.30 and 733.80
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.