Worksheet Grade 7 Math

Marlstone Pressure Zone: A Grade 7 Scale-Drawing Worksheet

A grade 7 worksheet where students read a scaled map of a fictional water system's pressure zone to find real pipe lengths and area, then redraw it at a new scale.

Objectives

  1. Students will use a map scale to find actual lengths and distances from measured map lengths.
  2. Students will compute the actual area of a rectangular pressure zone from its map dimensions.
  3. Students will reproduce map lengths and areas at a different scale and explain how they change.

Vocabulary

Pressure zone
A pressure zone is a section of a water system that a utility manages separately because it sits at a different elevation than the rest of the town. Utilities create pressure zones so that water pressure stays safe and steady for everyone, whether they live at the bottom of a hill or near the top.
Water main
A big underground pipe that carries drinking water beneath the streets to a neighborhood. Smaller service lines branch off it to reach each building.

Also: scale, area

Teacher overview

Utilities split a town into pressure zones and keep scaled maps of the water mains inside each one. This worksheet gives students a scaled map of a fictional zone and asks them to recover true lengths, a true area, and a redrawn map at a new scale. The common error to watch for is students treating an area the way they treat a length: when the scale doubles, lengths on the map halve, but the map area shrinks to one fourth, and items 8 and 10 make that difference explicit.

Answer Key

  1. Answer: 1,500 meters.
    6 cm × 250 meters per cm = 1,500 meters.
  2. Answer: 1.5 kilometers.
    1,500 meters ÷ 1,000 = 1.5 kilometers.
  3. Answer: 1,100 meters.
    4.4 cm × 250 meters per cm = 1,100 meters.
  4. Answer: 2,000 meters by 1,250 meters.
    Width: 8 cm × 250 = 2,000 meters. Height: 5 cm × 250 = 1,250 meters.
  5. Answer: 2,500,000 square meters.
    2,000 meters × 1,250 meters = 2,500,000 square meters.
  6. Answer: 800 meters.
    3.2 cm × 250 meters per cm = 800 meters.
  7. Answer: 3 cm.
    The main is 1,500 meters long. 1,500 ÷ 500 meters per cm = 3 cm on the new map.
  8. Answer: 4 cm by 2.5 cm.
    Width: 2,000 ÷ 500 = 4 cm. Height: 1,250 ÷ 500 = 2.5 cm.
  9. Answer: Shorter.
    Each centimeter now stands for 500 meters instead of 250, so the same real distance needs fewer centimeters on the map.
  10. Answer: Area depends on two lengths, so halving each cuts it twice.
    Both the width and the height were cut in half, and one half times one half is one fourth, so 40 square centimeters became 10 square centimeters.

Differentiation

Support

Provide the scale as a labeled rule at the top of the page, "1 cm on the map = 250 meters in real life," and let students set up each length problem as a multiplication before they compute. Pre-fill item 4's setup so students only carry out the two multiplications.

Extension

Ask students to redraw the map at a third scale, 1 cm = 1,000 meters, list the new length of every feature, and describe the pattern they notice in how the map lengths shrink each time the scale number doubles.

ELL supports

Pair the words "width," "height," "length," and "distance" with arrows drawn on a sample rectangle. Provide a two-column table labeled "map length (cm)" and "real length (meters)" so students can organize items 1, 3, and 6 before writing sentences.