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If the angles of a triangle are 30^(@) a...

If the angles of a triangle are `30^(@) and 45^(@)`, and the included side is `(sqrt3 + 1)` cm, then

A

area of the triangle is `(1)/() (sqrt3 + 1)` sq. units

B

area of the triangle is `(1)/(2) (sqrt3 -1)` sq. units

C

ratio of greater side to smaller side is `(sqrt3 + 1)/(sqrt2)`

D

ratio of greater side to smaller side is `(1)/(4sqrt3)`

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The correct Answer is:
To solve the problem step by step, we will follow the given information and apply the relevant mathematical concepts. ### Step-by-Step Solution: 1. **Identify the Angles and the Included Side:** Given angles of the triangle are: - Angle A = 30° - Angle B = 45° - The included side (between angle A and angle B) is \( \sqrt{3} + 1 \) cm. 2. **Calculate the Third Angle:** Using the property that the sum of angles in a triangle is 180°: \[ \text{Angle C} = 180° - \text{Angle A} - \text{Angle B} = 180° - 30° - 45° = 105° \] 3. **Apply the Sine Rule:** The Sine Rule states that: \[ \frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C} \] Here, we have: - Side a (opposite angle A) is unknown. - Side b (opposite angle B) is unknown. - Side c (opposite angle C) is the included side, which is \( \sqrt{3} + 1 \). 4. **Set Up the Equations Using the Sine Rule:** From the Sine Rule, we can write: \[ \frac{\sqrt{3} + 1}{\sin 105°} = \frac{b}{\sin 30°} = \frac{c}{\sin 45°} \] Rearranging gives: \[ b = \frac{(\sqrt{3} + 1) \cdot \sin 30°}{\sin 105°} \] \[ c = \frac{(\sqrt{3} + 1) \cdot \sin 45°}{\sin 105°} \] 5. **Calculate the Values of b and c:** We know: - \( \sin 30° = \frac{1}{2} \) - \( \sin 45° = \frac{\sqrt{2}}{2} \) - \( \sin 105° = \sin(90° + 15°) = \sin 15° = \frac{\sqrt{6} - \sqrt{2}}{4} \) Substitute these values into the equations: \[ b = \frac{(\sqrt{3} + 1) \cdot \frac{1}{2}}{\sin 105°} \] \[ c = \frac{(\sqrt{3} + 1) \cdot \frac{\sqrt{2}}{2}}{\sin 105°} \] 6. **Calculate the Area of the Triangle:** The area \( A \) of the triangle can be calculated using the formula: \[ A = \frac{1}{2} \cdot b \cdot c \cdot \sin A \] Substitute the values of b, c, and \( \sin A \): \[ A = \frac{1}{2} \cdot \left(\frac{(\sqrt{3} + 1) \cdot \frac{1}{2}}{\sin 105°}\right) \cdot \left(\frac{(\sqrt{3} + 1) \cdot \frac{\sqrt{2}}{2}}{\sin 105°}\right) \cdot \sin 30° \] 7. **Simplify the Area Expression:** After substituting and simplifying, we will find: \[ A = \frac{1}{2} \cdot \frac{(\sqrt{3} + 1)^2 \cdot \frac{1}{2} \cdot \frac{\sqrt{2}}{2}}{\sin^2 105°} \] 8. **Final Area Calculation:** After performing the calculations, we will find the area of the triangle.

To solve the problem step by step, we will follow the given information and apply the relevant mathematical concepts. ### Step-by-Step Solution: 1. **Identify the Angles and the Included Side:** Given angles of the triangle are: - Angle A = 30° - Angle B = 45° ...
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