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What is the value of b rounded to the nearest tenth

What is the value of b rounded to the nearest tenth-example-1
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User Metaxal
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8.4k points

1 Answer

3 votes

Answer:

b ≈ 29.7 units

Explanation:

Because we don't know whether this is a right triangle, but have an angle sandwiched between two sides, we can use the law of cosines to find b.

The law of cosines is given by the following formula:

(1.) a^2 = b^2 + c^2 - 2bc * cos(A)

(2.) b^2 = a^2 + c^2 -2ac * cos(B)

(3.) c^2 = a^2 + b^2 - 2ab * cos(C)

Because angle B is sandwiched between a and c, we can use formula 2 by plugging in 45 for a, 23 for c, and 36 for B.

Step 1: Plug everything in and simplify:

b^2 = a^2 + c^2 -2ac * cos(B)

b^2 = 45^2 + 23^2 - 2(45)(23) * cos(36)

b^2 = 2025 + 529 - 2070 * cos(36)

b^2 = 2554 - 2070 * cos(36)

b^2 = 879.3348216

Step 2: Take the square root of both sides to find b and then round to the nearest tenth:

√b^2 = ± √879.3348216

b = 29.65358025

b = 29.7

Although taking the square root of number gives you a positive and negative number since squaring both a positive and negative number give you a positive answer (e.g., 2 * 2 = 4 and -2 * -2 = 4), we can only use the positive answer since you can't have a negative measure. Thus, b is approximately 29.7 units.

answered
User YanDatsiuk
by
7.7k points

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