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麻烦解决英文数学题1.I have a triangular graden in my backyard.One sid

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麻烦解决英文数学题
1.I have a triangular graden in my backyard.One side is 4 meters and another side 6 meter.The angle that is formed by these two sides is 72 degreees.What is the area of the garden?
2.Jill's car tires are spinning at a rate of 120 revolutions per minute.If her car tires'radii are each 14 inches,how many yards does she travel in 5 minutes?
3.The figure shows a circle with center Y.Assume minor arc PO=minor arc EK.prove that line PO is congruent to line EK.
麻烦解决英文数学题1.I have a triangular graden in my backyard.One sid
1.½ x 4 x 6 x sin72° = 12 x sin72° ≈ 11.41 m³
2.轮胎半径R = 14英寸 = 14/36 = 7/18 码
2π x 7/18 x 120 x 5 = 1400π/3 ≈ 466.67 码
3.连接PY、OY、EY、KY
扇形PYO的面积 = ½ x 弧PO x 圆半径R
扇形EYK的面积 = ½ x 弧EK x 圆半径R
∵ 劣弧PO = 劣弧EK
∴ 扇形PYO的面积 = 扇形EYK的面积
又∵ 扇形PYO的面积 = ∠PYO x πR² / 360°
扇形EYK的面积 = ∠EYK x πR² / 360°
∴ ∠PYO = ∠EYK
在△PYO和△EYK中,
PY = EY
∠PYO = ∠EYK
OY = KY
∴ △PYO ≌ △EYK
∴ PO = EK