Answer: 143.49 cm
Explanation:
270/300 = 0.9
243/270 = 0.9
Each rebound is 90%
After 1st bounce, height = 0.9 x300
After 2nd bounce, height = 0.9^2 ×300
After nth bounce, height = 0.9^n x 300
Therefore, after 7th bounce, height = 0.9^7 x 300
= 143.49 cm