1. In the figure given below, < ABC and < BDC are right angles; If AB-5cm, AD = 3cm and BD = 4cm (3 points) find BC and DC ?

Answer :

In the given figure, the length of BC is 6.66 cm and the length of DC is 5.33 cm

Trigonometry

From  the question, we are to determine the length of BC and DC

Considering the diagram,

First, we will determine the measure of angle A

Using SOH CAH TOA

We can write that

[tex]sin A = \frac{4}{5}[/tex]

sin A = 0.8

∴ A = sin⁻¹(0.8)

A = 53.13°

Now, we will determine the measure of angle C

∠A + ∠ABC + ∠C = 180° (Sum of angles in a triangle)

53.13° + 90° + ∠C = 180°

∠C = 180° - 90° - 53.13°

∠C = 36.87°

Also,

Using SOH CAH TOA

[tex]tan C = \frac{BD}{DC}[/tex]

[tex]tan36.87 ^\circ=\frac{4}{DC}[/tex]

[tex]0.7500 = \frac{4}{DC}[/tex]

[tex]DC = \frac{4}{0.75}[/tex]

DC = 5.33 cm

By the Pythagorean theorem,

/BC/² = /BD/² + /DC/²

/BC/² = 4² + 5.33²

/BC/² = 16 + 28.4089

/BC/² = 44.4089

/BC/ = √44.4089

/BC/ = 6.66 cm

Hence, the length of BC is 6.66 cm and the length of DC is 5.33 cm

Learn more on Trigonometry here: https://brainly.com/question/3642956

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