Question

perhatikan segitiga berikut, kemudian tentukan nilai sin a, cos a, dan tan a
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Answer 1

a. y = 12

r = 20

sisi yang belum diketahui = x

x² = r² - y²

= 20² - 12²

= 400 - 144

= 256

x = √256 = 16

maka

• sin a = y/r = 12/20 = 3/5

• cos a = x/r = 16/20 = 4/5

• tan a = y/x = 12/16 = 3/4

b. x = 8

y = 4

sisi yang belum diketahui = r

r² = x² + y²

= 8² + 4²

= 64 + 16

= 80

r = √80 = √(16x5) = 4√5

• sin a = x/r

= 8/4√5

= 2/√5 x √5/√5

= (2√5)/5

• cos a = y/r

= 4/4√5

= 1/√5 x √5/√5

= (√5)/5

• tan a = x/y

= 8/4

= 2