Answer:
The measures of the three interior angles of the triangle are {40,55,85}.
Step-by-step explanation:
Let a = the measure of the first angle of the triangle.
Let b = the measure of the second angle of the triangle.
Let c = the measure of the third angle of the triangle.
The problem statement tells us that
(1) a = a
(2) b = a + 15 and
(3) c = a + 45
Now we (should) know that the sum of the three angles of a triangle is 180 degrees. Then we get
(4) a + b + c = 180 or by substitution we get
(5) a + (a + 15) + (a + 45) = 180 or
(6) a + a + 15 + a + 45 = 180 or
(7) 3*a + 60 = 180 or
(8) 3*a = 180 - 60 or
(9) 3*a = 120
Now divide both sides of (9) by 3 to get
(10) 3*a/3 = 120/3 or
(11) a = 40
Using (2) and (3) we get
(12) b = 40 + 15 or
(13) b = 55 and
(14) c = 40 + 45 or
(15) c = 55
Always check the answer. Use (4)
Is (40 + 55 + 85 = 180)?
Is (95 + 85 = 180)?
Is (180 = 180)? Yes
