Page 151 - Math Course 1 (Book 1)

Standard Form and Scientif c Notation

Plan SPACE
To f nd how many times farther Pluto is from the Use the table to estimate how many times farther
Sun than Mercury is from the Sun, f nd the ratio of Pluto is from the Sun than Earth is from the Sun.
Pluto’s distance to Mercury’s distance. Since you
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are estimating, round the distance 5.90 × 10 to Planet Distance from the sun (km)
7
9
6.0 × 10 and round the distance 5.80 × 10 to
7
6.0 × 10 . Mercury 5.80 x 10 7
Solve Venus 1.03 x 10 8
6.0 x 10 9 = 1.0 x 10 2 8
6.0 x 10 7 Earth 1.55 x 10
Mars 2.28 x 10 8
2
So, Pluto is about 1.0 ×10 or 100 8
Answer times farther from the Sun than Jupiter 7.78 x 10
Mercury is. Saturn 1.43 x 10 9
Uranus 2.87 x 10 9
Check Neptune 4.50 x 10 9
Use estimation to check the reasonableness of
the results. Pluto 5.90 x 10 9

A. 3
B. 30
C. 38
D. 300
SPACE Answer
The diameters of Mercury, Saturn,
3
and Pluto are 4.9 × 10 kilometers,
5
3
1.2 × 10 kilometers, and 2.3 × 10
kilometers, respectively. List the
planets in order of increasing diameter.
First, order the numbers according to their Order the numbers 6.21 × 105, 2.35 × 104, 5.95 ×
exponents. 109, and 4.79 × 104 in decreasing order.

Then, order the numbers with the same exponent
5
4
4
by comparing the factors. A. 2.35 × 10 , 4.79 × 10 , 6.21 × 10 ,
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and 5.95 × 10
4
9
5
Mercury and Pluto Saturn B. 6.21 × 10 , 5.95 × 10 , 4.79 × 10 ,
and 2.35 × 10 4
9
4
4
5
3
Step 1 4.9 × 10 < 1.2 × 10 C. 2.35 × 10 , 4.79 × 10 , 5.95 × 10 ,
and 6.21 × 10 5
2.3 × 10 3
5
4
9
D. 5.95 × 10 , 6.21 × 10 , 4.79 × 10 ,
and 2.35 × 10 4
3
3
Step 2 2.3 × 10 < 4.9 × 10 Compare the
factors: 2.3 < 4.9.
Pluto Mercury Answer
So, the order is Pluto, Mercury,
Answer
and Saturn
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