Question

600 m
250 m
300 m
Lake
19. What is the approximate number of
meters across the longest part of the lake
shown in the diagram above?
(1) 1150
(2) 720
(3)
550
(4)
500
(5)
125
G

Answer 1

From the given picture, we can note that the small triangle is isosceles because the base angles are equal. Additionally, we can note that the big triangle and the small one are similar. Then, we can draw the following picture:

The similarity allow us to write the following equation:

$\frac{d}{600}=\frac{250}{300}$

where d represents the longest part of the lake. Then, by multiplying both sides by 600, we get

$\begin{gathered} d=600\times\frac{250}{300} \\ d=2\times250 \\ d=500 \end{gathered}$

Therefore, the answer is option (4)