Home / 1,121.28-1,680.64-512

Finding the Fourth Proportional to 1,121.28, 1,680.64 and 512

Calculator

Solution

The fourth proportional to 1,121.28, 1,680.64 and 512 is: 767.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,121.28 : 1,680.64 = 512 : x
  2. Step 2: Convert to fraction form
    1,121.28/1,680.64 = 512/x
  3. Step 3: Cross multiply
    1,121.28x = 1,680.64 × 512
  4. Step 4: Simplify right side
    1,121.28x = 860,487.68
  5. Step 5: Solve for x
    x = 860,487.68/1,121.28
  6. Step 6: Final answer
    x = 767.42

Related Problems

Find fourth proportional to 560.64, 840.32 and 256
Half scale
Find fourth proportional to 2,242.56, 3,361.28 and 1,024
Double scale
Find fourth proportional to 1,122.28, 1,682.14 and 513
Similar ratio
Find fourth proportional to 1,681.92, 2,520.96 and 768
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.