## Sunday, 22 July 2012

### Trigonometry Activity 1

Group Activity 1

1. Farrell, Dylan, Bryan, Sherwin, Harindrar, Edwin7/24/2012 10:03 am

Solution 1: Take a picture of a ruler beside the flag pole. Then use a photo editing software to copy, paste and stack up the ruler until it reaches the height of the flagpole. Read the length from the ruler.

Solution 2: Put a ruler a certain distance away from the flagpole. Imagine a line from the top of the flagpole to the top of the ruler, to the floor. Mark the point where the line hits the floor. Measure to ratio of the distance of the flagpole to the point to the distance of the ruler to the point. The ratio of the height of the ruler to the height of the flag pole is the same ratio.

2. Yan Feng,Bowen,Praveen,Ryan,Darshan

Solution 1:The triangle of interest is FAB. We have measured two angles of this
triangle: angle A (measured elevation from A), angle B (equal to 180
deg - elevation from B), and angle F (180 deg - A - B).
Using the Law of Sines, we can write
dist(BA) dist(FA)
------- = ------- this allows us to calculate the
sin(F) sin(B) distance FA.
And then we apply trigonometry to the right triangle FOA:

Solution 2:

Find a stick the length of your arm. Hold your arm out straight with the stick pointing straight up (90 degree angle to your outstretched arm). Walk backwards until you see the tip of the stick line up with the top of the tree. Your feet are now at approximately the same distance from the tree as it is high. (Provided the tree is significantly taller than you are, and the ground is relatively level.)

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4. Solution: Ask a person to to stand beside the flagpole, take a picture. Then measure the the height of the person and the flagpole in the picture and then you can find out the scale ratio by the the real height of the person and the height o the person int he image. Using that ratio you can find out the height of the flagpole.

Image (object) Image (pole) Real (object) Real (pole)
1.4cm 4.6cm 1.75m 5.75m
1.8cm 6.15cm 1.565m 5.35m
2.1cm 6.4cm 1.8m 5.48m

Done by : Chinni,Wei qin,wai kit,jereme,lindsay,shiying