Answer:
Δ QRS is an obtuse triangle ⇒ according to its angle
Δ QRS is an isosceles triangle ⇒ according to its sides
Explanation:
In Δ QRS
∵ m∠Q = 8x - 17
∵ m∠R = 19x + 4
∵ m∠S = 5x + 1
→ The sum of the interior angles of a Δ is 180°
∴ m∠Q + m∠R + m∠S = 180°
→ Substitute their values in the equation above
∵ 8x - 17 + 19x + 4 + 5x + 1 = 180
→ Add the like terms
∴ (8x + 19x + 5x) + (-17 + 4 + 1) = 180
∴ 32x + (-12) = 180
∴ 32x - 12 = 180
→ Add 12 to both sides
∵ 32x - 12 + 12 = 180 + 12
∴ 32x = 192
→ Divide both sides by 32
∵
=
∴ x = 6
→ Substitute the value of x in each measure of angles to find them
∵ m∠Q = 8(6) - 17 = 48 - 17
∴ m∠Q = 31°
∵ m∠R = 19(6) + 4 = 114 + 4
∴ m∠R = 118°
∵ m∠S = 5(6) + 1 = 30 + 1
∴ m∠S = 31°
∵ m∠R > 90°
∴ ∠R is an obtuse angle
∴ Δ QRS is an obtuse triangle
∵ m∠Q = m∠S
→ In any Δ if two angles are equal in measures, then the two sides
opposite to these angles are equal in length and the Δ is isosceles
∴ RQ = RS
∴ Δ QRS is an isosceles triangle