A triangle has perimeter 59 cm. The lengths of the sides are 2x – 5 cm, 3x + 2 cm and 2x – 1 cm.
1 answer:
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The size of angle PRQ is 15°
Step-by-step explanation:
In any regular polygon of n-sided
- All sides are equal in length
- All angles are equal in measure
- The measure of each interior angle is
- The measure of each exterior angle is
- The sum of the measures of the interior and exterior angle at the same vertex is 180°
∵ PQ and QR are two sides of a regular 12-sided polygon
∴ PQ = QR
∵ PR is a diagonal
∴ ∠PQR is an interior angle of the polygon
- By using the rule of the interior angle above
∵ n = 12
∴ m∠PQR =
∴ m∠PQR = 150°
In Δ PQR
∵ PQ = QR ⇒ sides in a regular polygon
- Δ PQR is an isosceles Δ
∴ m∠PRQ = m∠RPQ ⇒ base angles of an isosceles Δ
The sum of the measures of the interior angles of a triangle is 180°
∵ m∠PQR + m∠PRQ + m∠RPQ = 180°
∴ 150 + m∠PRQ + m∠RPQ = 180°
- Subtract 150 from both sides
∴ m∠PRQ + m∠RPQ = 30
∵ m∠PRQ = m∠RPQ
- Divide their sum by 2 to find the measure of each one
∴ m∠PRQ = m∠RPQ = 30 ÷ 2 = 15°
∴ m∠PRQ = 15°
The size of angle PRQ is 15°
Learn more:
You can learn more about the triangles in brainly.com/question/3945600
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