Water is the Adjacent of this right triangle. 350 yards is the length of the Hypotenuse. We have given angle B, 40 degrees.
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According to SOH CAH TOA, we use CAH (cosineΘ = adjacent/hypotenuse).
- Θ = 40
- hyoptenuse = 350
- adjacent = x
cosine40 = x/350
[multiply both sides by 350]
350 · cosine40 = x
[put calculator in degree mode]
x ≈ 268 yards
So, the distance across the water from sailboat to the island is 268 yards.
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Let's use pythagorean theorem since we already know the adjacent and hypotenuse to find the opposite <em>(opposite is also known as height</em>).
a^2 + b^2 = c^2
- a = ? (opposite or height)
- b = 268 (adjacent)
- c = 350 (hypotenuse)
a^2 + (268)^2 = (350)^2
a^2 + 71824 = 122500
a^2 = 122500 - 71824
a^2 = 50676
[square both sides]
=
a =
a ≈ 225
So, the height, opposite, of the lighthouse is 225 yards.
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<h2>
ANSWER: </h2><h2>
a) 268 yards </h2><h2>
b) 225 yards</h2>