Ryan is putting a clothesline in his rectangular backyard. He wants to put it between two trees on the edge of his property. He has measured his property, and made the sketch shown below, where all the lengths listed are in meters. What is the smallest length of rope that Ryan could buy which would stretch from one tree to the other?

Explanation:  

The first figure attached is the sketch of the property mentioned on the question, where all the lengths listed are in meters.

The second figure attached identifies a right triangle whose hypotenuse, c, is the smallest length that the clothesline can measure; and the legs measure 20m, and 20m - 10m = 15m.  

Now, you can use the Pythagorean theorem to find the smallest length of the clothesline:  

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m

step-by-step explanation:

you divide the denominator by the numerator on both sides and if the quotients are equal then the fractions are equivalent