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BA= BD
AC=13
CD=14
ABC=(x+2)°
CBD=37°
[?]

BA= BD AC=13 CD=14 ABC=(x+2)° CBD=37° [?]-example-1
User SamClem
by
4.0k points

1 Answer

3 votes

Answer:

-2 < x < 32.3

Explanation:

You want to know the range of the possible values of x in the given figure with two adjacent triangles.

Solution

Angle ABC will be the largest it can be when ∆ABC is isosceles. That is, AB=CB=DB. The law of cosines can be used to find the angle.

Let AB=CB=DB=a, then the law of cosines tells us for ∆CBD ...

14² = a² +a² -2a·a·cos(37°) = 2a²(1 -cos(37°))

Similarly, for ∆ABC, we have ...

13² = 2a²(1 -cos(x+2)°)

The ratio of these two equations is ...

13²/14² = (2a²(1 -cos(x+2)°))/(2a²(1 -cos(37°))

1 -cos(x +2)° = (13/14)²(1 -cos(37°)) . . . . . multiply by (1-cos(37°))

cos(x +2)° = 1 -(13/14)²(1 -cos(37°)) . . . . . solve for cos(x+2)°

x = arccos(1 -(13/14)²(1 -cos(37°))) -2° . . . . solve for x

x ≈ 32.3° . . . . . maximum value of x

The minimum value of x will be -2, when angle ABC is 0°. This can happen at extreme lengths of BC (long or short).

-2 < x < 32.3

BA= BD AC=13 CD=14 ABC=(x+2)° CBD=37° [?]-example-1
BA= BD AC=13 CD=14 ABC=(x+2)° CBD=37° [?]-example-2
User Janica
by
3.9k points