Midsegment of triangle
find the distance across the lake

The distance across the lake is 3.5 km

Step-by-step explanation:

Hypotenuse is divided in equal parts. Thus both sides are divided in the same proportion.

if you are saying purchasing 3 social media ads and one newspaper ad counts as one purchase then there are:

6 purchases

if you are asking how many of each then:

18 social media ads

6 newspaper ads