Math Problem Statement

Determine length b to the nearest tenth of a centimetre for the triangle with sides and angles: AB = 27.2 cm, ∠B = 72°, ∠C = 43°.

Solution

To solve for the length bb in the given triangle, we can apply the Law of Sines. The Law of Sines states:

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

Where:

  • a=27.2cma = 27.2 \, \text{cm}
  • A=43A = 43^\circ
  • B=72B = 72^\circ
  • C=180(43+72)=65C = 180^\circ - (43^\circ + 72^\circ) = 65^\circ

Now we can use the ratio:

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

Substitute the known values:

bsin72=27.2sin43\frac{b}{\sin 72^\circ} = \frac{27.2}{\sin 43^\circ}

Solve for bb:

b=27.2×sin72sin43b = \frac{27.2 \times \sin 72^\circ}{\sin 43^\circ}

Using approximate values for the sine functions:

b=27.2×0.95110.682025.8740.682037.93b = \frac{27.2 \times 0.9511}{0.6820} \approx \frac{25.874}{0.6820} \approx 37.93

To the nearest tenth of a centimeter, b37.9cmb \approx 37.9 \, \text{cm}.

Would you like more details on this process or help with further steps?

Here are five related questions:

  1. What is the Law of Cosines and when would you use it?
  2. How would you calculate the length of side cc in this triangle?
  3. What are the applications of the Law of Sines in real-world problems?
  4. How do you determine if a triangle is obtuse or acute?
  5. Why is it important to know the sum of angles in a triangle?

Tip: Always ensure angle measurements are in degrees or radians as needed for trigonometric calculations.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Law of Sines
Triangle Angles

Formulas

Law of Sines: (a/sinA) = (b/sinB) = (c/sinC)
Sum of Angles in a Triangle: ∠A + ∠B + ∠C = 180°

Theorems

Law of Sines

Suitable Grade Level

Grades 10-11