Home / 519.78-774.78-505.20

Finding the Fourth Proportional to 519.78, 774.78 and 505.20

Calculator

Solution

The fourth proportional to 519.78, 774.78 and 505.20 is: 753.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    519.78 : 774.78 = 505.20 : x
  2. Step 2: Convert to fraction form
    519.78/774.78 = 505.20/x
  3. Step 3: Cross multiply
    519.78x = 774.78 × 505.20
  4. Step 4: Simplify right side
    519.78x = 391,418.86
  5. Step 5: Solve for x
    x = 391,418.86/519.78
  6. Step 6: Final answer
    x = 753.05

Related Problems

Find fourth proportional to 259.89, 387.39 and 252.60
Half scale
Find fourth proportional to 1,039.56, 1,549.56 and 1,010.40
Double scale
Find fourth proportional to 520.78, 776.27 and 506.20
Similar ratio
Find fourth proportional to 779.67, 1,162.17 and 757.80
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.