Pythagorean Theorem is
a ²+ b ² = c ²
a and b are the shorter sides, while c is the hypotenuse, or longest side. Let’s say the side we are looking for is “b”.
Let’s first rearrange the equation, then sub in.
a ²+ b ² = c ²
b ² = c ²- a ²
b = √ (c ²- a ²)
b = √(17 ²- 15 ²)
b = √(289-225)
b = √ 64
b = 8
In 8rows and 3 in each so 8 times 3 is 24
If .5cm is 2km, then 1 cm is 4 km, and therefore 120/4 is 30, so 30 centimeters on the map
We know, shortest distance between two points
and
is :

So, distance between house and library is :

Distance between library and post office :

Distance between post office and house :

Therefore, minimum distance that you can ride your bike is (5.39+7.07+7) km = 19.46 km.
Hence, this is the required solution.