Question

Algebra 1 Grade 9.

Can anyone please help me answer this question?

The brightness of a star is measured in magnitudes. The lower the magnitude, the brighter the star. A magnitude 9 star is 2.51 times as bright as a magnitude 10 star. A magnitude 8 star is 2.51 * 2.51 or (2.51)2 as bright as a magnitude 10 star.

(Note: 10 - 8 = 2. Get it?)

A. How many times as bright is a magnitude 3 star as a magnitude 10 star?

B. Write an expression to compare a magnitude m star to a magnitude 10 star.

C. A full moon is magnitude -13, approximately. Does your expression make sense for this magnitude? Explain.

Answer 1

627.65 times

2.51^(10 - m) times

Yes, it makes sense

Explanation:

Given that,

A magnitude 9 star is 2.51 times as bright as a magnitude 10 star

To find

a)

How many times as bright is a magnitude 3 star as a magnitude 10 star

10 - 3 = 7

2.51^7

627.65 times

b)

Expression to compare a magnitude m star to a magnitude 10 star

2.51^(10 - m) times

c)

Yes, it makes sense as a full moon is magnitude -13

so,

2.51^(10 - (-13))

2.51^(23)

1557742231 times