## chris215 one year ago An airplane leaves an airport and flies due west 150 miles and then 170 miles in the direction S 49.17°W. How far is the plane from the airport (round to the nearest mile)?

1. chris215

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2. chris215

i know that 90 + 49.17 = 139.17

3. chris215

now do I use c^2=a^2+b^2?

4. anonymous

90 + 49.17

5. chris215

yeah is that all i need to do?

6. anonymous

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7. chris215

= 150^2 + 170^2 - 2(150)(170cos)(139.17) = 226 miles

8. anonymous

angle as i have shown in the figure angle is (180-49.17)

9. anonymous

$\cos (180-49.17)=-\cos 49.17$

10. anonymous

$- \cos 49.17=\frac{ 150^2+170^2-OB^2 }{ 2*150*170 }$

11. anonymous

$5100 *(-\cos 49.17)=22500+28900-OB^2$