Math Problem Statement

Determine the perimeter of the following shape.

Solution

To calculate the perimeter of the given shape, we need to add up the lengths of all its sides.

  1. Given Information:

    • Straight sides: 4cm,4cm,7cm,5cm4 \, \text{cm}, 4 \, \text{cm}, 7 \, \text{cm}, 5 \, \text{cm}
    • A curved side: This is a circular arc of a sector.
  2. Find the length of the arc: The length of an arc LL is given by: L=rθL = r \theta where rr is the radius of the circle and θ\theta is the angle in radians.

    • Radius r=4cmr = 4 \, \text{cm}
    • Angle θ=40=40π180radians=2π9radians\theta = 40^\circ = \frac{40 \pi}{180} \, \text{radians} = \frac{2\pi}{9} \, \text{radians}

    Substituting into the formula: L=4×2π9=8π9cm2.79cmL = 4 \times \frac{2\pi}{9} = \frac{8\pi}{9} \, \text{cm} \approx 2.79 \, \text{cm}

  3. Calculate the total perimeter: Add the straight sides and the arc length: Perimeter=4+4+7+5+2.79=22.79cm\text{Perimeter} = 4 + 4 + 7 + 5 + 2.79 = 22.79 \, \text{cm}

Final Answer:

The perimeter of the shape is approximately 22.79 cm.

Would you like further clarification or assistance with similar problems? Here are some related questions for practice:

  1. How do you calculate the area of the circular sector in this problem?
  2. What is the total angle in radians for a complete circle?
  3. How would the perimeter change if the angle were 60° instead of 40°?
  4. Can the formula for arc length be used for any curve? Why or why not?
  5. How is the radian measure related to degrees?

Tip: Always remember to convert angles to radians when using formulas involving circular motion or sectors!

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Math Problem Analysis

Mathematical Concepts

Geometry
Arc Length
Perimeter Calculation

Formulas

Arc length formula: L = rθ
Perimeter formula: Sum of all sides

Theorems

Angle conversion: Degrees to Radians

Suitable Grade Level

Grades 7-10