Home / 630.76-870.50-398.12

Finding the Fourth Proportional to 630.76, 870.50 and 398.12

Calculator

Solution

The fourth proportional to 630.76, 870.50 and 398.12 is: 549.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    630.76 : 870.50 = 398.12 : x
  2. Step 2: Convert to fraction form
    630.76/870.50 = 398.12/x
  3. Step 3: Cross multiply
    630.76x = 870.50 × 398.12
  4. Step 4: Simplify right side
    630.76x = 346,563.46
  5. Step 5: Solve for x
    x = 346,563.46/630.76
  6. Step 6: Final answer
    x = 549.44

Related Problems

Find fourth proportional to 315.38, 435.25 and 199.06
Half scale
Find fourth proportional to 1,261.52, 1,741 and 796.24
Double scale
Find fourth proportional to 631.76, 871.88 and 399.12
Similar ratio
Find fourth proportional to 946.14, 1,305.75 and 597.18
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.