Question

Adding and Subtracting with Rational Numbers

The elevation we call sea level is actually the average level of the sea. This means that at average sea level, the elevation is zero. In reality, the level of the sea rises and falls in what are called tides. Low tide is the point of lowest sea level in a tidal period. High tide is the point of highest sea level in a tidal period. The height above or below average sea level is called elevation. An elevation below sea level is considered a negative value, while an elevation above sea level is positive.

Winston lives near the ocean. He regularly brings an altimeter to the beach to measure the elevation of the ocean’s surface. You will use the data Winston gathered to complete tasks about the rising and falling of the ocean’s surface. When necessary, sketch a diagram of the situation on a separate sheet of paper to assist you.

On Monday at 1 p.m., when the ocean’s surface was at an elevation of 2.2 feet, Winston went to a surf shop that was 8.2 feet above the ocean’s surface. At 7 p.m. when the ocean’s surface was at an elevation of -2.4 feet, Winston ate dinner at a restaurant whose deck was 10 feet above the ocean’s surface.

Part A
What was the net change in the elevation of the ocean’s surface from 1 p.m. to 7 p.m.?


Part B
How many feet apart are the two ocean elevations described in part A?

Part C
What is the elevation of the deck where Winston ate dinner?

Part D
What is the elevation of the surf shop?

Part E
What was the distance between the deck and the ocean’s surface at 1 p.m.? Which was higher, the deck or the ocean?

Part F
What was the distance between the surf shop and the ocean’s surface at 7 p.m.? Which was higher, the surf shop or the ocean?
plzzz help 100 points

Answer 1

Answers :-

Part A

It changed from 2.2 ft to -2.4 ft

Part B

Distance between elevation => Ocean elevation A + Ocean Elevation B = 2.2 + 2.4 = 4.6 ft

Part C

Winston ate dinner at a restaurant whose deck was 10 feet above the ocean’s surface.

Part D

In the sentence "Winston went to a surf shop that was 8.2 feet above the ocean’s surface". So, 8.2 ft

Part E

Height of shop - Height of elevation at top

=> 8.2 - 2.2 = 6 ft

Part F

12.4 ft is the height of surf shop

Surf shop was Higher

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Answer 2

Part A

Net change is the change compared to zero level

• From positive 2.2 feet to negative 2.4 feet

Part B

The distance between the elevations

• 2.2 + 2.4 = 4.6 feet

Part C

• 10 feet

Part D

• 8.2 feet

Part E

Positive elevation brings the level close to the deck

• 8.2 - 2.2 = 6 feet

Part F

Negative elevation takes the level apart from the elevation of the surf shop

• 10 - (-2.4) = 12.4 feet
• The surf shop was higher