Pls help with the following sums:- 1) If 343 is the third proportional of a and b, where a:b = 1:7, then find the value of a+b2) If a:b = 4:5 and b:c = 2:3, then a:c = ?

Pls help with the following sums:- 1) If 343 is the third proportion

1.	Pls help with the following sums:- 1) If 343 is the third proportional of a and b, where a:b = 1:7, then find the value of a+b2) If a:b = 4:5 and b:c = 2:3, then a:c = ?
Answer» 1)82)4:3Explanation:hope it is the ANSWER just trying to helpplzzzz.... put BRAINALIST