Find the area $A$ of a cone if radius $r = 1.26 cm$ and slant height $l = 3.9 cm$ .

Answer

$6.5016 cm^{2}$

Explanation

STEP 1: find base area $A B$

To find base area $A B$ use formula:

A B = r^{2} \cdot π

After substituting $r = 1.26 cm$ we have:

A B = (1.26 cm)^{2} \cdot π

A B = 1.5876 cm^{2} \cdot π

STEP 2: find Curved Surface Area $CS A$

To find Curved Surface Area $CS A$ use formula:

CS A = l \cdot r \cdot π

After substituting $r = 1.26 cm$ and $l = 3.9 cm$ we have:

CS A = 3.9 cm \cdot 1.26 cm \cdot π

CS A = 3.9 cm \cdot 1.26 cm \cdot π

CS A = 4.914 π cm^{2}

STEP 3: find area $A$

To find area $A$ use formula:

A = A B + CS A

After substituting $A B = 1.5876 π cm^{2}$ and $CS A = 4.914 π cm^{2}$ we have:

A = 1.5876 π cm^{2} + 4.914 π cm^{2}

A = 1.5876 cm^{2} + 4.914 cm^{2}

A = 6.5016 cm^{2}

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Find the area A of a cone if radius r=1.26cm and slant height l=3.9cm.

6.5016cm2

Find the area $A$ of a cone if radius $r = 1.26 cm$ and slant height $l = 3.9 cm$ .

$6.5016 cm^{2}$