Answer: 10.1 cm approximately
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Explanation:
The double tickmarks show that segments DE and EB are the same length.
The diagram shows that DB = 16 cm long
We'll use these facts to find DE
DE+EB = DB
DE+DE = DB
2*DE = DB
DE = DB/2
DE = 16/2
DE = 8
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Now let's focus on triangle DEC. We just found the horizontal leg is 8 units long. The vertical leg is EC which is unknown for now. We'll call it x. The hypotenuse is CD = 9
Use the pythagorean theorem to find x
a^2+b^2 = c^2
8^2+x^2 = 9^2
64+x^2 = 81
x^2 = 81 - 64
x^2 = 17
x = sqrt(17)
That makes EC to be exactly sqrt(17) units long.
If you follow those same steps for triangle ADE, then you'll find the missing length is AE = 6
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So,
AC = AE+EC
AC = 6 + sqrt(17)
AC = 10.1231056256177
AC = 10.1 cm approximately
