Luca is designing a propeller system that consists of 3 blades, each of which is identical. The blades are sectors of a circle that have radii of 4 inches and central angles of 20 . The blades are to be made from steel that weighs 16 grams per square inch. Determine the weight of the three blades together to the nearest gram.

Total weight of blades = ~134gm

Step-by-step explanation:

Radius of circle, = 4 inches

Central angle of sector =

For finding the weight of blades, we need to find the area of blades.

Area of circle, A =

We know that circle has a central angle of .

We can use unitary method to find the area of sector with angle .

Area of central angle =

Area of central angle =

Area of central angle =

Putting value of r = 4 inches

Area of blade:

We have 3 blades here, so area of 3 blades =

Weight of steel = 16 grams per square inch

Total weight of all 3 blades = 16 8.38 = ~ 134gm

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