Solve =20^2+13^2-21^2/2*20*21

$$= \frac { 20 ^ { 2 } + 13 ^ { 2 } - 21 ^ { 2 } } { 2 \times 20 \times 21 }$$

Evaluate

$$\frac{16}{105}\approx 0.152380952$$

Solution Steps

Calculate 20 to the power of 2 and get 400.

$$\frac{400+13^{2}-21^{2}}{2\times 20\times 21}$$

Calculate 13 to the power of 2 and get 169.

$$\frac{400+169-21^{2}}{2\times 20\times 21}$$

Add 400 and 169 to get 569.

$$\frac{569-21^{2}}{2\times 20\times 21}$$

Calculate 21 to the power of 2 and get 441.

$$\frac{569-441}{2\times 20\times 21}$$

Subtract 441 from 569 to get 128.

$$\frac{128}{2\times 20\times 21}$$

Multiply 2 and 20 to get 40.

$$\frac{128}{40\times 21}$$

Multiply 40 and 21 to get 840.

$$\frac{128}{840}$$

Reduce the fraction \frac{128}{840} to lowest terms by extracting and canceling out 8.

$$\frac{16}{105}$$

Factor

$$\frac{2 ^ {4}}{3 \cdot 5 \cdot 7} = 0.1523809523809524$$