Question

what is the value of x in the diagram below? if necessary round your answer to the nearest tenth of a until

Answer 1

Answer: the other answer for apex for the pre test is 6.5

Explanation:

Answer 2

C

Explanation:

Calculate AC using Pythagoras' identity in ΔABC

AC² = 20² - 12² = 400 - 144 = 256, hence

AC =
`√(256)` = 16

Now find AD² from ΔACD and ΔABD

ΔACD → AD² = 16² - (20 - x)² = 256 - 400 + 40x - x²

ΔABD → AD² = 12² - x² = 144 - x²

Equate both equations for AD², hence

256 - 400 + 40x - x² = 144 - x²

-144 + 40x - x² = 144 - x² ( add x² to both sides )

- 144 + 40x = 144 ( add 144 to both sides )

40x = 288 ( divide both sides by 40 )

x = 7.2 → C