Home / 513.50-770.25-128.75

Finding the Fourth Proportional to 513.50, 770.25 and 128.75

Calculator

Solution

The fourth proportional to 513.50, 770.25 and 128.75 is: 193.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    513.50 : 770.25 = 128.75 : x
  2. Step 2: Convert to fraction form
    513.50/770.25 = 128.75/x
  3. Step 3: Cross multiply
    513.50x = 770.25 × 128.75
  4. Step 4: Simplify right side
    513.50x = 99,169.69
  5. Step 5: Solve for x
    x = 99,169.69/513.50
  6. Step 6: Final answer
    x = 193.13

Related Problems

Find fourth proportional to 256.75, 385.13 and 64.38
Half scale
Find fourth proportional to 1,027, 1,540.50 and 257.50
Double scale
Find fourth proportional to 514.50, 771.75 and 129.75
Similar ratio
Find fourth proportional to 770.25, 1,155.38 and 193.13
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.