Download Dinosaurs

Name_________________________________________________________
CCSS
6.EE.7
Date __________
Dinosaurs
Read the following portion of a magazine article about studies of a
Tyrannosaurus rex skeleton.
Initial estimates indicated that the T. rex weighed 4.6 tons. A second
estimate years later with scanning equipment indicated that the dinosaur
weighed 6.5 tons. The third and most recent estimate indicated that the
dinosaur weighed 140% of the previous estimate. It also estimates that
in its peak growing years, a T. rex gained 4000 pounds per year.
1. Which equation can you use to find the weight increase x (in tons) from
the initial estimate to the second estimate?
A. 4.6 − x = 6.5
B. 4.6 + x = 6.5
C. 6.5 x = 4.6
D. 6.5 + x = 4.6
2. Which increase in estimated weight was greater, the increase from the
initial estimate to the second estimate, or the increase from the second
estimate to the most recent estimate? Justify your answer.
3. Suppose a T. rex weighs 3 tons when it enters its peak growing years.
How long would it take the T. rex to double in weight? Explain how
you found your answer.
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Big Ideas Math
Performance Tasks
13
CCSS
6.EE.7
Common Core State Standard
6.EE.7 Solve real-world and mathematical problems by writing and solving equations
of the form x + p = q and px = q for cases in which p, q and x are all
nonnegative rational numbers.
CCSS
6.EE.7
Grading Rubric
Answers
Score
1. B
1
2. increase from second estimate to most recent; 2.6 > 1.9
2
3. 1.5 yr; Used the rate to find how long it would take the T. rex to
gain 3 tons.
2
Precision
1. Student reasons that the equation is a simple addition equation.
1
2. Student calculates and compares the increases.
2
3. Student interprets the doubling in weight in terms of pounds.
Student realizes that units must be converted and uses the rate
to find the time.
Total Points
14
Big Ideas Math
Performance Tasks
2
10
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All rights reserved.