Sirius A is 8.6 light-years from Earth. What is this distance in kilometers? What is this distance in feet?

a. 8.136 × 10¹³ km b. 2.669 × 10¹⁹ feet

Explanation:

a. What is this distance in kilometers?

Since Sirius A is 8.6 light years away from Earth and one light year = distance travelled by light in a year = 3 × 10⁸ m/ s × 365 days/year × 24 hr/day × 3600 s/hr = 9.4608 × 10¹⁵ m = 9.4608 × 10¹² km.

Then 8.6 light years = 8.6 × 1 light year

= 8.6 × 9.4608 × 10¹² km

= 81.363 × 10¹² km

= 8.1363 × 10¹³ km

≅ 8.136 × 10¹³ km

b.  What is this distance in feet?

Since 1 meter = 3.28 feet,

8.6 light years = 8.1363 × 10¹² km

= 8136.3 × 10¹⁵ m

= 8136.3 × 10¹⁵ × 1 m

= 8136.3 × 10¹⁵ × 3.28 feet

= 26687.1  × 10¹⁵ feet

= 2.66871 × 10¹⁹ feet

≅ 2.669 × 10¹⁹ feet

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