Subscribe

4th grade · Math · Unit 10 of 17

Angles & Area

Acute, right, obtuse and area

What your child practices

Sorting angles into acute, right, obtuse and straight, finding area by multiplying length by width, and working backward to find a side.

New York State Learning Standards learning standard: NY-4.MD.5; NY-4.G.1; NY-4.MD.3 · lines and angles, acute, right and obtuse angles, and the area formula for rectangles

How we explain it

Children can open this short lesson before they practice.

  1. Area is the space inside. Length × width for a rectangle.
  2. A right angle is a square corner (90°). Acute is smaller. Obtuse is bigger.
  3. Area is measured in square units, like cm².

Example: A rectangle is 4 cm long and 3 cm wide. What is its area? Multiply length by width. 4 × 3 = 12. Answer: 12 square cm

Angles & Area in New York

In the New York State Learning Standards, this is unit 10 of 17 in 4th grade Math, after Fractions and before Metric Measures.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: New York State Education Department (NYSED)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    A straight line makes what kind of angle?

    • obtuse angle
    • right angle
    • straight angle

  2. Question 2

    A rectangle is 13 cm long and 4 cm wide. What is its area in square centimeters?

    answer box

  3. Question 3

    What kind of angle is this?

    • right
    • straight
    • acute
    • obtuse

  4. Question 4

    A rectangle is 11 cm long and 5 cm wide. What is its area in square centimeters?

    answer box

  5. Question 5

    A rectangle has an area of 30 square centimeters. It is 6 cm long. How wide is it, in centimeters?

    6 × = 30

    answer box

  6. Question 6

    What kind of angle is this?

    • obtuse
    • right
    • acute
    • straight

More 4th grade