Question

Given △PQR ~ △STU, find the missing measures in △STU.

Triangles P Q R and S T U. Side P Q has length 14, side Q R has length 28, and side R P has length 21. Angle P has measure 70 degrees and angle R has measure 46 degrees. In triangle S T U, side U S has length 6. No other measures are given.

SU ST TU m∠S m∠T m∠U

Answer 1

Explanation:

Since △PQR ~ △STU, their corresponding angles are congruent, and their corresponding sides are proportional.

First, we can find the measure of angle Q as follows:

m∠Q = 180 - m∠P - m∠R = 180 - 70 - 46 = 64 degrees

Next, we can use the fact that the sides of the similar triangles are proportional to set up the following proportions:

frac{ST}{21} = frac{SU}{14} and frac{ST}{28} = frac{TU}{21}

Solving for ST gives us:

ST = frac{21}{14} SU = frac{3}{2} SU

and

ST = frac{28}{21} TU = frac{4}{3} TU

Substituting these values into the second proportion, we get:

frac{3}{2} SU = frac{4}{3} TU

Multiplying both sides by 2/3, we get:

SU = frac{8}{9} TU

Now we can use the fact that the angles in a triangle add up to 180 degrees to find the measure of angle T.

m∠T = 180 - m∠S - m∠U = 180 - m∠S - (180 - m∠P - m∠R)

m∠T = m∠P + m∠R - m∠S = 70 + 46 - m∠S = 116 - m∠S

Finally, we can use the fact that the angles in △STU add up to 180 degrees to find the measure of angle S.

m∠S + m∠T + m∠U = 180

Substituting the previously found values for m∠T and SU into the equation, and solving for m∠S gives us:

m∠S = 52 degrees

Therefore, the missing measures are:

SU = 6 x 8/9 = 16/3

ST = 3/2 x 6 = 9

TU = 4/3 x 9 = 12

m∠S = 52 degrees

m∠T = 116 - 52 = 64 degrees

m∠U = 180 - 52 - 64 = 64 degrees