Respuesta :

Answer:

∠BAC = 35°

AC = 5 cm

BD = 2.4 cm

Step-by-step explanation:

As ΔABC ~ ΔBDC then ∠CBD ≅ ∠BAC

As ∠CBD = 35° then ∠BAC = 35°

Using Pythagoras' Theorem

CB² + AB² = AC²

⇒ 3² + 4² = AC²

⇒ 25 = AC²

AC = 5 cm

As ΔABC ~ ΔBDC then

AB : AC = BD : BC

⇒ 4 : 5 = BD : 3

[tex]\sf \implies \dfrac45=\dfrac{BD}{3}[/tex]

[tex]\sf \implies BD=\dfrac{12}{5}=2.4\:cm[/tex]

**A right triangle with legs of 3cm and 4cm, and a perpendicular line from the hypotenuse to the right angle vertex, does not have an internal angle CBD of 35°.  It should be 36.87°.  So if you use SOHCAHTOA to find the length of BD, it will be incorrect. See attached diagram**

Ver imagen semsee45

Answer:

  • 35°, 5 units, 2.4 units

Step-by-step explanation:

Given

  • ΔABC ~ ΔBDC

Corresponding angles are congruent

  • ∠BAC ≅ ∠DBC
  • m∠BAC = m∠DBC = 35°

Use Pythagorean to find the length of AC

  • [tex]AC = \sqrt{AB^2+BC^2} =\sqrt{3^2+4^2} =\sqrt{25} =5[/tex]

The ratio of corresponding sides is equal

  • BD/AB = BC/AC
  • BD/4 = 3/5
  • BD = 4*3/5
  • BD = 2.4