سؤال**: يمتلك دائرة محيطًا يبلغ 31.4 سم. احسب مساحتها. - Verified Servers

February 24, 2026 · Verified Servers

["Title: How to Calculate the Area of a Circle? A Step-by-Step Guide Using the Circumference", "Meta Description:
\nEver wondered how to calculate the area of a circle when given only its circumference? Learn the step-by-step method using the formula and example: if a circle’s circumference is 31.4 cm, discover its area using just this measurement.", "---", "### Understanding the Relationship Between Circumference and Area of a Circle", "When studying geometry, one of the most fundamental questions is: How do we find the area of a circle when we only know its circumference? This problem is common in math education and real-world applications, such as architecture, engineering, and design.", "In this article, we’ll solve a practical example: finding the area of a circle whose circumference is 31.4 cm, and explain the mathematical reasoning behind it. Whether you're a student, teacher, or curious learner, understanding this process will boost your geometry skills.", "---", "### Step 1: Recall Key Circle Formulas", "To calculate the area from the circumference, we first need the relationship between the two.", "- Circumference formula:
\n \( C = 2\pi r \)
\n where \( C \) is the circumference and \( r \) is the radius.", "- Area formula:
\n \( A = \pi r^2 \)
\n where \( A \) is the area and \( r \) is the radius.", "Our challenge: Given \( C = 31.4 \) cm, compute \( A \), but we first need to find \( r \).", "---", "### Step 2: Find the Radius from the Circumference", "Using the circumference formula:", "\[
\nC = 2\pi r
\n\]", "Solve for \( r \):", "\[
\nr = \frac{C}{2\pi}
\n\]", "Plug in \( C = 31.4 \) cm (and \( \pi \approx 3.14 \)):", "\[
\nr = \frac{31.4}{2 \ imes 3.14} = \frac{31.4}{6.28} = 5 \ ext{ cm}
\n\]", "So, the radius of the circle is 5 cm.", "---", "### Step 3: Calculate the Area", "Now that we have \( r = 5 \) cm, use the area formula:", "\[
\nA = \pi r^2 = \pi \ imes 5^2 = \pi \ imes 25
\n\]", "Using \( \pi = 3.14 \):", "\[
\nA = 3.14 \ imes 25 = 78.5 \ ext{ cm}^2
\n\]", "---", "### Final Answer: The area of the circle is 78.5 square centimeters.", "---", "### Why This Formula Works", "The key insight is that the circumference defines the circle’s perimeter, and using \( \pi \approx 3.14 \), we link linear measurement (circumference) to area (which involves squaring the radius). This demonstrates why the area of a circle grows quadratically with radius, while circumference grows linearly.", "---", "### Real-World Application", "Understanding how to compute area from circumference helps in fields where measurements are limited or imprecise. For example:", "- Construction: Estimating material needs based on measured circular openings
\n- Engineering: Designing pipes, turbines, or tanks with circular cross-sections
\n- Daily life: Calculating garden beds, circular tables, or pizza slices (yes, that’s geometry too!)", "---", "### Summary", "- Given: Circumference \( C = 31.4 \) cm
\n- Formula: \( r = \frac{C}{2\pi} \), then \( A = \pi r^2 \)
\n- Result: Area \( A = 78.5 \) cm²", "Now you know how to calculate the area of a circle — even when only the circumference is given. Keep practicing with different values, and explore how changes in circumference affect area!", "---", "Keywords for SEO:
\ncircle area calculation, circumference to area formula, how to find circle area given circumference, geometry problem solve 31.4 cm, calculate circle area from circumference, practical geometry example, problem solving circle area", "Tags:

\n

CircleFormulas #Geometry #MathTutorial #AreaCalculator #CircumferenceToArea #STEMEducation", "---", "If you found this guide helpful, share it with fellow learners and explore more geometry tutorials to build a strong foundation in mathematics!"]

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