9514 1404 393
Answer:
12 units
Step-by-step explanation:
The ratio of the base to the other sides is ...
4 : 7 : 7
The perimeter is a total of 4 +7 +7 = 18 ratio units, so each ratio units stands for 54/18 = 3 length units.
The base length is then ...
(4 ratio units)(3 length units/ratio unit) = 12 length units
