Double Half Angle Worksheets Grade 12

Geometry

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Each printable worksheet below is a full page of practice problems and comes with an answer key that explains how to solve every problem, step by step. Open a worksheet and use the Print / Save as PDF button to download it.

Worksheet 1

8 problems
  1. An architectural firm is designing a modern building with a triangular glass facade. The angle between two support beams is measured as θ, where cos θ = -3/5 and θ lies in the second quadrant. To calculate the stress distribution, engineers need to find the exact value of sin(θ/2). What is the exact value of sin(θ/2)?
  2. Given that sin(θ) = 3/5 and θ is in the first quadrant, find the exact value of sin(2θ) + cos(2θ).
  3. sin(2θ) = 4/5 and θ is in the first quadrant, find cos(4θ) = ?

…and 5 more problems

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Worksheet 2

8 problems
  1. A circular archway is modeled by the function f(x) = 12cos(x/3) over the interval [-3π/2, 3π/2], where x represents horizontal distance in meters and f(x) represents height in meters. Using double-angle formulas, determine the exact height of the archway at x = π/2 meters.
  2. Given that sin(2θ) = 24/25 and cos(θ) > 0, find cos(4θ) = ?
  3. sin(2θ) = 3/5, cos(2θ) = 4/5, find sin²(θ) = ?

…and 5 more problems

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Worksheet 3

6 problems
  1. An architect is designing a modern art installation that features a triangular metal sculpture. The sculpture has sides of length 8 meters and 10 meters with an included angle θ. The architect needs to calculate the exact area of the sculpture, which is given by the formula A = ½(8)(10)sinθ. Through measurements, she determines that cosθ = 3/5. Using double-angle or half-angle formulas, find the exact area of the triangular sculpture.
  2. Kaia is a conservation biologist tracking the flight path of a rare native bird. She observes that the bird's trajectory forms an angle θ with the ground, where θ is in the first quadrant. Using radar data, she determines that cos(2θ) = 11/61. To model the bird's altitude relative to its horizontal distance, Kaia needs the exact value of sin(θ). Using double-angle or half-angle formulas, what is the exact value of sin(θ)?
  3. An architect is designing a modern art sculpture that consists of a triangular metal frame. The frame forms an isosceles triangle where the vertex angle is θ. Through precise measurements, the architect determines that cos(θ) = -3/5. To calculate the exact length of the base supports, she needs to find sin(θ/2). What is the exact value of sin(θ/2)?

…and 3 more problems

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