ABCD is a trapezium AD and BC are parallel

Part (a)

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Work Shown:

We'll apply the sine rule since we have a known opposite side of AB = 10 and an unknown hypotenuse we want to find BD.

Focus on triangle ABD

sin(angle) = opposite/hypotenuse

sin(D) = AB/BD

sin(56) = 10/x

x*sin(56) = 10

x = 10/sin(56)

x = 12.062179

x = 12.1

Make sure your calculator is in degree mode.

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Part (b)

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Work Shown:

Draw an xy coordinate grid.

Place point A at the origin (0,0).

Point B is 10 units above this, so B is at (0,10).

Point C is at (18,10) since we move 18 units to the right of B.

Point D is at approximately (6.745085, 0). The 6.745085 is from solving tan(56) = 10/x for x.

Refer to the diagram below.

Apply the distance formula for the points C and D.

Segment CD is roughly 15.1 cm long.