The right triangle is also Isosceles. It has two equal angles of 45°.
(hypotenuse)² = 2S²
4 = 2S² => S = √2
Therefore B is the correct answer.
If the triangles are similar, then the corresponding ratio of their sides have equal ratios. Through ratio and proportion, we would determine the answer.
5/6 = x/9, where x is the length for side PN
Transposing the equation so that x is on the left side:
x = (5/6)*9
x = 7.5
Answer:
The number of trees at the begging of the 4-year period was 2560.
Step-by-step explanation:
Let’s say that x is number of trees at the begging of the first year, we know that for four years the number of trees were incised by 1/4 of the number of trees of the preceding year, so at the end of the first year the number of trees was
, and for the next three years we have that
Start End
Second year 
-------------- 
Third year 
-------------
Fourth year 
--------------
So the formula to calculate the number of trees in the fourth year is
we know that all of the trees thrived and there were 6250 at the end of 4 year period, then
⇒
Therefore the number of trees at the begging of the 4-year period was 2560.
Here is some thoughts on this:
cos 57 = sin (90-57) = sin 33
so cos 57 . cosec 33 = cos 57 / sin 33 = sin 33 / sin33 = 1
2 cos 60 = 2 * 1/2 = 1
so the last 2 parts work out to 0
now we have to find cos 70 / sin 20
sin 20 = cos 70 so this comes to 1
so finally the answer is 1
