Question

In diagram, what is AC?

Answer 1

you can use Pythagorean theory on this one a^2+b^2+c^2 so first you need to find DB a^2+8^2=17^2 a^2=225 a=15 next you need AD which can be found by subtracting DB from AB so 21-15=6 AB=6 then we use Pythagorean again this time on the smaller triangle 6^2+8^2=c^2 c^2 is AC 36+64=c^2 100=c^2 10=c AC=10

Answer 2

AC = 10 units

Explanation:

In the given right angle triangle BCD

`BC^(2)=BD^(2)+CD^(2)`

By putting BC = 17 and CD = 8

`17^(2)= BD^(2)+8^(2)`

`BD^(2)=17^(2)-8^(2)=289-64`

`BD^(2)=225`

`BD=√(225)=15`

Now in ΔACD

`AC^(2)=AD^(2)+CD^(2)`

`AC^(2)=(AB-DB)^(2)+CD^(2)` [since AD = AB-DB]

`=(21-15)^(2)+8^(2)`

`=6^(2)+8^(2)`

= 36 + 64

= 100

`AC=√(100)=10units`