Answer Key — HSG.SRT.D.9

For parents and tutors

Do not share with students before practice tests.

Practice Problems — Sets 1–10

| Set | Guidance | | --- | --- | | Set 1 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 2 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 3 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 4 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 5 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 6 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 7 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 8 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 9 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 10 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. |

Practice Problems — Sets 11–20

| Set | Guidance | | --- | --- | | Set 11 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 12 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 13 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 14 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 15 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 16 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 17 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 18 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 19 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. | | Set 20 | (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle b… — verify written work and accept reasonable drawings. |

Review tiers 1–10

Checklists are parent-judged.
Written items: verify against practice set patterns.
Standard text: (+) Derive the formula A = 1/2 ab sin(C) for the area of a triangle by drawing an auxiliary line from a vertex perpendicular to the opposite side.

Practice test scoring

| Tier | Pass guidance | | --- | --- | | 1–3 | Most oral tasks smooth; majority of written correct | | 4–6 | 7/10+ total with clear understanding | | 7–8 | 9/12+ with explanations | | 9–10 | Near-perfect; ready to move on |

___________________________ ___________________________ ___________________________ ___________________________ ___________________________ ___________________________