Question

Please I don’t understand help me?!

Answer 1

BD = 35

Explanation:

Calculate CD in right triangle ABC, then BD in right triangle BCD

Using Pythagoras' identity in both triangles.

The square on the hypotenuse is equal to the sum of the squares on the other two sides.

In Δ ADC

CD² + AD² = AC² , substitute values

CD² + 9² = 15²

CD² + 81 = 225 ( subtract 81 from both sides )

CD = 144 ( take the square root of both sides )

CD =
`√(144)` = 12

----------------------------------------------------------------

In Δ BCD

BD² + CD² = BC² , substitute values

BD² + 12² = 37²

BD² + 144 = 1369 ( subtract 144 from both sides )

BD² = 1225 ( take the square root of both sides )

BD =
`√(1225)` = 35

Answer 2

35 units

Explanation:

First find CD, consider BC is hypotenuse

• CD= √15²-9²= √225-81= √144= 12 units

Then find BD, consider AC is hypotenuse

• BD= √37²-12²= √1369- 144= √1225= 35 units