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Zorluk: Çok zorRight Triangles and the Pythagorean Theorem

In triangle ABCABC, the measure of angle ABCABC is 9090^\circ and the measure of angle BACBAC is 3030^\circ. Segment BDBD is perpendicular to segment ACAC such that DD lies on ACAC. Segment DEDE is perpendicular to segment BCBC such that EE lies on BCBC. If the length of segment CECE is 33, what is the length of segment ACAC?

Cevap: 24

Cevap

The correct answer is 24.
The correct answer is 24. Since the question asks for the length of segment AC, and by sequentially applying the properties of 30-60-90 right triangles we find CD = 6, BC = 12, and AC = 24.

Adım Adım Çözüm

1
Find the measure of angle ACBACB in triangle ABCABC.
ACB=60\angle ACB = 60^\circ
The sum of the angles in a triangle is 180180^\circ, so ACB=180ABCBAC=1809030=60\angle ACB = 180^\circ - \angle ABC - \angle BAC = 180^\circ - 90^\circ - 30^\circ = 60^\circ.
2
Calculate the length of segment CDCD using right triangle DECDEC.
CD=6CD = 6
In the right triangle DECDEC, DEC=90\angle DEC = 90^\circ and C=60\angle C = 60^\circ, making it a 30-60-90 triangle. The side opposite the 3030^\circ angle is CE=3CE = 3, so the hypotenuse CDCD is 2×CE=2×3=62 \times CE = 2 \times 3 = 6.
3
Calculate the length of segment BCBC using right triangle BDCBDC.
BC=12BC = 12
In the right triangle BDCBDC, BDBD is perpendicular to ACAC, so BDC=90\angle BDC = 90^\circ. With BCD=60\angle BCD = 60^\circ, this is a 30-60-90 triangle. The side opposite the 3030^\circ angle is CD=6CD = 6, so the hypotenuse BCBC is 2×CD=2×6=122 \times CD = 2 \times 6 = 12.
4
Calculate the length of the hypotenuse ACAC using right triangle ABCABC.
AC=24AC = 24
In the right triangle ABCABC, the angle BAC=30\angle BAC = 30^\circ and the side opposite to it is BC=12BC = 12. The hypotenuse ACAC is twice the length of the opposite leg, so AC=2×BC=2×12=24AC = 2 \times BC = 2 \times 12 = 24.

Anahtar Kavram

Properties of special right triangles (30-60-90 triangles) and their trigonometric ratios.
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