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Please help this is an homework assignment

Please help this is an homework assignment-example-1
User Semiflex
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1 Answer

4 votes

Answer:

300 in²

Explanation:

You want the area of a TV screen with a 25-inch diagonal and a 15-inch height.

Pythagorean theorem

To find the area, you need to know the screen width. You can find it using trigonometry, but it is probably more straightforward to find it using the Pythagorean theorem. That tells you the square of the diagonal is the sum of the squares of the height and width:

w² +15² = 25²

w² = 625 -225 = 400

w = √400 = 20 . . . . inches

Area

The area of a rectangle 15 inches high and 20 inches wide is ...

A = LW

A = (20 in)(15 in) = 300 in²

The area of the screen is 300 square inches.

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Additional comment

The angle between the side and the diagonal at upper left is ...

cos(α) = 15/25

α = arccos(15/25) ≈ 53.13°

Then the width of the screen is ...

w = 25·sin(53.13°) = 20 . . . . inches

User Stacy
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