Step-by-step explanation: We know that 6 and 12 are related, 6 times 2 is 12 so if you do the same for 4 and you multiply 4 by 2 you get 8 for the blank side, then subtract 1 from 8 to get 7. Same for the bigger triangle, 6 times 2 is 12 subtracted by 1 is 11.
(21 + 34 + x + 25 + 37 + 22) / 6 = 30 (139 + x) / 6 = 30 .....multiply both sides by 6 139 + x = 30 * 6 139 + x = 180 x = 180 - 139 x = 41......so during week 3, she rode her bike 41 miles
