The tangent of an angle is the ratio of the opposite side to the adjacent side.
... tan(45°) = (height above eye level)/(20 m)
... height above eye level = (20 m)·tan(45°) = (20 m)·1 = 20 m
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Eye level is 1.7 m above ground, so the height of the flagpole above ground is
... height of pole = height above eye level + height of eye level
... height of pole = 20 m + 1.7 m = 21.7 m
1/5 of a litre is 0.2 litres
1 litre minus 0.2 litres is 0.8 litres so
0.8 divided by 5 (glasses) is 0.16 litres in each glass
The process of expressing w in terms of A and l is called transposition or changing the subject of the formula. The methods used to change the subject of the formula are the same as those used for solving equations.
So basically you just need to do the Pythagorean theorem to find the sides of the shaded rectangle, with c being the length of the side.
Small side:
2^2 + 6^2 = c^2
4 + 36 = c^2
40 = c^2
C is similar to 6.32456
Long side:
12^2 + 4^2 = c^2
144 + 16 = c^2
160=c^2
C is similar to 12.64911
And then you just multiply!
