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In the diagram, ℓ$_{5}$ ∥ ℓ$_{1}$, and ℓ$_{2}$ ∥ ℓ$_{6}$. The transversals ℓ$_{3}$ and ℓ$_{4}$ cut the parallel lines. The marked angles are 54°, 93°, 54°, 28° and 93°. Calculate the value of each marked unknown, giving a reason for every answer.

In the figure, ℓ$_{5}$ ∥ ℓ$_{3}$, and ℓ$_{2}$ ∥ ℓ$_{1}$. The transversals ℓ$_{6}$ and ℓ$_{4}$ cut the parallel lines. The marked angles are 75°, 43°, 75°, 75° and 43°. Calculate the value of each marked unknown, giving a reason for every answer.

An isosceles triangle has an altitude of 11 cm drawn from its apex perpendicular to its base. The base measures 16 cm. Calculate the value of each marked unknown, giving a reason for every answer.

Study the diagram: ℓ$_{6}$ ∥ ℓ$_{2}$, and ℓ$_{5}$ ∥ ℓ$_{1}$. The transversals ℓ$_{3}$ and ℓ$_{4}$ cut the parallel lines. The marked angles are 100°, 33°, 133° and 57°. Calculate the value of each marked unknown, giving a reason for every answer.

Study the diagram: ℓ$_{1}$ ∥ ℓ$_{5}$, and ℓ$_{3}$ ∥ ℓ$_{2}$. The transversals ℓ$_{6}$ and ℓ$_{4}$ cut the parallel lines. The marked angles are 28°, 83°, 83°, 83° and 144°. Calculate the value of each marked unknown, giving a reason for every answer.

In the diagram, ℓ$_{4}$ ∥ ℓ$_{2}$, and ℓ$_{6}$ ∥ ℓ$_{3}$. The transversals ℓ$_{1}$ and ℓ$_{5}$ cut the parallel lines. The marked angles are 87°, 55°, 87°, 142° and 142°. Calculate the value of each marked unknown, giving a reason for every answer.

In the diagram, ℓ$_{6}$ ∥ ℓ$_{4}$, and ℓ$_{3}$ ∥ ℓ$_{1}$. The transversals ℓ$_{2}$ and ℓ$_{5}$ cut the parallel lines. The marked angles are 66°, 122°, 155° and 66°. Calculate the value of each marked unknown, giving a reason for every answer.

Study the diagram: ℓ$_{2}$ ∥ ℓ$_{4}$, and ℓ$_{3}$ ∥ ℓ$_{1}$. The transversals ℓ$_{5}$ and ℓ$_{6}$ cut the parallel lines. The marked angles are 71°, 67°, 138°, 71° and 33°. Calculate the value of each marked unknown, giving a reason for every answer.

Study the diagram: ℓ$_{3}$ ∥ ℓ$_{4}$, and ℓ$_{5}$ ∥ ℓ$_{2}$. The transversals ℓ$_{1}$ and ℓ$_{6}$ cut the parallel lines. The marked angles are 90°, 28°, 56°, 90° and 90°. Calculate the value of each marked unknown, giving a reason for every answer.

Study the diagram: ℓ$_{1}$ ∥ ℓ$_{2}$, and ℓ$_{4}$ ∥ ℓ$_{3}$. The transversals ℓ$_{5}$ and ℓ$_{6}$ cut the parallel lines. The marked angles are 48°, 85°, 60°, 133° and 133°. Calculate the value of each marked unknown, giving a reason for every answer.

In the diagram, ℓ$_{6}$ ∥ ℓ$_{3}$, and ℓ$_{1}$ ∥ ℓ$_{5}$. The transversals ℓ$_{2}$ and ℓ$_{4}$ cut the parallel lines. The marked angles are 25°, 63°, 46°, 134° and 71°. Calculate the value of each marked unknown, giving a reason for every answer.

Study the diagram: ℓ$_{2}$ ∥ ℓ$_{1}$, and ℓ$_{5}$ ∥ ℓ$_{4}$. The transversals ℓ$_{6}$ and ℓ$_{3}$ cut the parallel lines. The marked angles are 96°, 96°, 65°, 96° and 39°. Calculate the value of each marked unknown, giving a reason for every answer.