Home / 729.78-1,007.09-398.19

Finding the Fourth Proportional to 729.78, 1,007.09 and 398.19

Calculator

Solution

The fourth proportional to 729.78, 1,007.09 and 398.19 is: 549.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    729.78 : 1,007.09 = 398.19 : x
  2. Step 2: Convert to fraction form
    729.78/1,007.09 = 398.19/x
  3. Step 3: Cross multiply
    729.78x = 1,007.09 × 398.19
  4. Step 4: Simplify right side
    729.78x = 401,011.18
  5. Step 5: Solve for x
    x = 401,011.18/729.78
  6. Step 6: Final answer
    x = 549.50

Related Problems

Find fourth proportional to 364.89, 503.54 and 199.10
Half scale
Find fourth proportional to 1,459.56, 2,014.17 and 796.38
Double scale
Find fourth proportional to 730.78, 1,008.46 and 399.19
Similar ratio
Find fourth proportional to 1,094.67, 1,510.63 and 597.29
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.