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Could anyone help me with number 25 THANK YOU!!!

Could anyone help me with number 25 THANK YOU!!!-example-1
User Vlumi
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1 Answer

3 votes

Answer:

ΔABC ~ ΔQPR by the Angle-Angle (AA) similarity theorem of two triangles

Explanation:

The coordinates of the vertices are given as follows;

A = (1, 2), B =(9, 8), C = (1, 8)

P= (5, -3), Q = (-7, 6), R = (-7, -3)

The given dimensions of AB and PQ are 10, and 15 respectively

The, l lengths of the sides of triangles are found as follows;


l = \sqrt{\left (y_(2)-y_(1) \right )^(2)+\left (x_(2)-x_(1) \right )^(2)}

For segment BC, we have;

B =(9, 8), C = (1, 8)

(x₁, y₁) = (9, 8), (x₂, y₂) = (1, 8), substituting gives;

Length BC = 8

For length CA, C = (1, 8) A = (1, 2)

(x₁, y₁) = (1, 8)

(x₂, y₂) = (1, 2)

The length found by substituting the values for (x₁, y₁), (x₂, y₂) in the length equation gives; Length CA = 6

Given that length CA² + BC² = 8² + 6² = 64 + 36 = 100 = BA², we have by Pythagoras theorem, we have ΔABC is a right triangle

Similarly, for ΔQPR, we have;

Length QR, Q = (-7, 6), R = (-7, -3) = 9

Length PR, P= (5, -3), R = (-7, -3) = 12

QR² + PR² = 9² + 12² = 225 = 15² = PQ²

∴ ΔQPR is a right triangle

By comparing the ratio of the sides, we have;

cos(θ) = PR/PQ = 12/15 = 4/5, θ = cos⁻¹(4/5) = 36.9°

∠RPQ = 36.9°

sin(θ) = QR/PQ = 9/15 = 3/5

Similarly in triangle ΔABC, we have;

cos(θ) = BC/AB = 8/10 = 4/5

∠CBA = 36.9°

Therefore, ∠CBA ≅ ∠RPQ = 36.9°

Also ∠PRQ ≅ ∠BCA = 90° (Angle opposite hypotenuse side of right triangle

Therefore, ΔABC and ΔQPR are similar triangles by the Angle-Angle (AA) similarity theorem of two triangles.

User Sheesh Mohsin
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