Answer:
28 cm per year
5.5 years
Explanation:
In three years time, the height of the tree grew from 190 to 274, that's an increase of 84 cm. Divice that by the number of years it took. So you get this calculation:
(274-190)/3 = 28
When the tree was 344 centimeters tall, the increase was 344-190 = 154. Divide that by the 28 found earlier to get 154/28 = 5.5 years.