Solve a formula for one letter

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Pia's triangle sign has area A = (1/2)bh: base b, height h. Solve A = (1/2)bh for h.

   h = 2A/b
2. 2.

   Ren's box has volume V = lwh. Solve V = lwh for w.

   w = V/(lh)
3. 3.

   Tala pays T = pn + s for n books: price p each plus a fee s. Solve T = pn + s for n.

   n = (T − s)/p
4. 4.

   Ari studies the line y = mx + b. Solve y = mx + b for b.

   b = y − mx
5. 5.

   Bo has a line in standard form, Ax + By = C. Solve Ax + By = C for y.

   y = (C − Ax)/B
6. 6.

   Esme writes a line through (a, b) as y − b = m(x − a). Solve this for b.

   b = y − m(x − a)
7. 7.

   Jun's line is Ax + By = C. Solve Ax + By = C for x.

   x = (C − By)/A
8. 8.

   Kira's triangle sign has area A = (1/2)bh. The area is 30 and the height is 6. What is the base b?

   10
9. 9.

   Milo's robot circuit has V = 12 volts and I = 3 amps, using V = IR. What is the resistance R?

   4
10. 10.

    Noah's rug has perimeter P = 30 and length l = 9, using P = 2l + 2w. What is the width w?

    6