If a 30-meter pine tree casts a shadow of 30 meter, how far is the tip of the shadow from top of the tree?

Answer 1

Just use Pythagoras ...
x^2 = 30^2+30^2 = 1800
x = √1800 = 30√2

or

the 30-3--x triangle is similar to the 1-1-√2 right-angled triangle
so x = 30√2