Using the formula (AB +BC) *BC = (DE +CD) *CD
fill i n what is known:
(17 + 4) *4 = (DE +6) *6
21*4 = (DE +6)*6
84 = (DE+6)*6
84/6 = DE+6
14 = DE +6
DE = 14-6
DE = 8
The answer is 6 centimeters
When multiplying by a number that is 1 with 0's on the end, you move the decimal to the right by how many zeros there are.
Because 10,000 has 5 0's, we move the decimal 5 places to the right.
8.88 => 88800