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the diagram shows triangle ABC, with AC=14 cm, BC=10 cm and angles ABC=63°
FIND THE ANGLE CAB
find the length of AB​


The Diagram Shows Triangle ABC With AC14 Cm BC10 Cm And Angles ABC63FIND THE ANGLE CABfind The Length Of AB class=

Sagot :

Answer:

Step-by-step explanation:To solve this problem, we can use the Law of Sines, which relates the sides of a triangle to the sines of their opposite angles. The Law of Sines states:

\[

\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}

\]

Given:

- \(AC = 14 \text{ cm}\)

- \(BC = 10 \text{ cm}\)

- \(\angle ABC = 63^\circ\)

We need to find:

1. \(\angle CAB\) (denoted as \(\angle A\))

2. The length of side \(AB\) (denoted as \(c\))

### Step 1: Find \(\angle A\) (using Law of Sines)

We know:

- \(b = AC = 14 \text{ cm}\)

- \(a = BC = 10 \text{ cm}\)

- \(\angle B = 63^\circ\)

Using the Law of Sines:

\[

\frac{a}{\sin A} = \frac{b}{\sin B}

\]

Substitute the known values:

\[

\frac{10}{\sin A} = \frac{14}{\sin 63^\circ}

\]

Now, solve for \(\sin A\):

\[

\sin A = \frac{10 \times \sin 63^\circ}{14}

\]

Calculate the value:

\[

\sin A = \frac{10 \times 0.8910}{14} \approx \frac{8.910}{14} \approx 0.636

\]

Now find \(\angle A\) (use the inverse sine function):

\[

\angle A \approx \sin^{-1}(0.636) \approx 39.5^\circ

\]

### Step 2: Find \(\angle C\)

We can find \(\angle C\) using the fact that the sum of the angles in a triangle is \(180^\circ\):

\[

\angle C = 180^\circ - \angle A - \angle B

\]

\[

\angle C = 180^\circ - 39.5^\circ - 63^\circ \approx 77.5^\circ

\]

### Step 3: Find the length of \(AB\) (using Law of Sines)

Using the Law of Sines again:

\[

\frac{c}{\sin C} = \frac{a}{\sin A}

\]

Substitute the known values:

\[

\frac{c}{\sin 77.5^\circ} = \frac{10}{\sin 39.5^\circ}

\]

Solve for \(c\):

\[

c = \frac{10 \times \sin 77.5^\circ}{\sin 39.5^\circ}

\]

Calculate the value:

\[

c = \frac{10 \times 0.9775}{0.6360} \approx \frac{9.775}{0.6360} \approx 15.37 \text{ cm}

\]

### Final Answers:

1. \(\angle CAB \approx 39.5^\circ\)

2. The length of \(AB\) is approximately \(15.37\) cm.