find the shaded areadiagram 9 shows a circle with centre O and another circle Q.The two circles touch at P and PQO is a straight line.calculate the area , in cm^2 ,of the shaded regionA.132 C.154B. 462 D.616use pai=22/7
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find the shaded areadiagram 9 shows a circle with centre O and another circle Q.The two circles touch at P and PQO is a straight line.calculate the area , in cm^2 ,of the shaded regionA.132 C.154B. 462 D.616use pai=22/7
find the shaded area
diagram 9 shows a circle with centre O and another circle Q.The two circles touch at P and PQO is a straight line.
calculate the area , in cm^2 ,of the shaded region
A.132 C.154
B. 462 D.616
use pai=22/7
find the shaded areadiagram 9 shows a circle with centre O and another circle Q.The two circles touch at P and PQO is a straight line.calculate the area , in cm^2 ,of the shaded regionA.132 C.154B. 462 D.616use pai=22/7
B
求阴影部分的面积
由图9及题目可知,OQ= r 1=7cm,即OP = r2 =14cm
小圆OQP的面积为:
SOQP = π x r1²
= π x 7 x 7
= 49π cm²
S大圆 = π x r2²
= π x 14 x 14
= 196π cm²
则阴影部分面积为
S阴影 = S大圆 - SOQP
= 196π - 49π
= 147π
若π ≈ 3.14
则S阴影 = 147 x 3.14
= 461. 58
≈ 462 cm²